This is about a standardized score vs. your locally-informed opinion.
It’s not inaccurate information. You are just using a different methodology (or not one at all 
than WalkScore is. You don’t agree with it, but I think if you look at how they come up with the score, it will make more sense to you.
I think what you are missing here is that Walk Score / Transit Score / Bike Score are specific scores made by a specific company with a specific and standardized methodology. They are actually registered trademarks, not just a general opinion on walkablility. There is a methodology for the score. It’s akin to an SAT score. Sure, you can do well on other standardized tests but that has nothing to do with your SAT score, which is specific with its own methodology. You’re welcome to say that you think your “most errands don’t require a car” at your listing, but you it doesn’t mean the same thing as when WalkScore does. Only you know what it means.
Personally, because I am familiar with Walk Score, it would be helpful to me as a guest. You’ve already proven that host’s ideas about walkability is subjective and not standardized. At least when I look at the WalkScore, I know what it means - because it’s standardized.
A score of 100 would reflect that you could do a great variety of errands, go to a variety of parks and recreation, eat and drink a great variety of cuisines, have numerous entertainment options and a variety of schools preferably within a 5 minute walk but at least in a 10 minute walk.
And yes it exists because my old address in NYC did indeed have a perfect 100 point Walk Score. Since I know what that was like as a pedestrian, I can guestimate how it would feel to get around walking somewhere with a 60 or 30 point score. The standardization makes it useful. A host’s opinion will always be subjective and is not as useful.
The UWS is an excellent standard. Here are the things I remember that I could do in a 5-10 min walk from my apt there (this is just what I remember): 5 laundry mats, 7 dry cleaners, several pet stores, electronics store, jewelry store and repair, shoe repair, walk-in clinic (flu shots and such), majory hospital for surgery/emergency room/birthing center, 3 different ballets, a few symphonies, an opera, 4 large and 2 small concert halls, 5 grocery stores, 6 speciality gourmet markets, at least 6 gyms, boat rentals and docks, car rentals, car repair shops, 2 skateboard shops, 2 post offices, shoe stores, coffee roasters, nut roasters, numerous boutiques, at least 9 liquor stores, 3 movie theaters, 3 regular theatres, upholsterery shop, fabric store, at least 7 optometrists, art classes, art supplies, segway rentals, 3 lingerie stores, 3 colleges, numerous medical professionals and specialists, veternarians, manicures and pedicures, hair salons, dentists, orthodontists, several physical therapy clinics, 2 places to see comedy, ice and roller skating, soccer fields, cooking classes, lifeguard certification, outdoor movies, indoor movies, yoga places, office supplies, 2 dog parks, drug stores, head shops, 20+ different cuisines, a dozen bars and taverns, 3 ice cream shops, 3 nursing homes, 3 assisted living facilities, numerous schools for various ages and religions, churches, mosques and synagogues for at least 12 denominations, a JCC and an an Islamic Cultural Center , 2 libraries, 4 bookstores, at least 5 antique shops, art galleries, 2 Goodwills, butcher shops, numerous hardware stores, 2 stationery stores, numerous playgrounds, parks, tennis courts, running paths, bike paths and sports fields, 4 museums, multiple landmarks, numerous hotels, handball courts, rock climbing, swimming, a dozen banks, real estate agents, import stores, furniture stores, plumbing supplies, appliance stores, Urban Outfitters/Marshalls/The North Face (and all that crap that’s like that), an incense emporium, at least 5 foot-massage studios, dance lessons, acting schools, psychiatrists, planned parenthood, 3 compounding pharmacies, multiples of all the drugstores, maybe 7 basket ball courts, bunch of daycares, hearing-aid shop, all the cell phone provider shops, psychics, medical uniform shop, numerous statues, bridal and tux shops, motorized w/c repair and sales, bike shops, beauty supplies, a furrier, at least 4 thrift and vintage shops (not including the 2 Goodwills), sporting goods, toy stores, eyebrow threading, a Judaism shop, numerous tailors, 2 hat shops, a reiki studio, an aromatherapy clinic, several day spas, several doggy daycares, 2 youth hostels, costume shop, a pickle shop, one of those places where kids paint plates and mugs, one of those places where grown folks paint and drink at the same time, Stawberry Fields and even a place where you could do a sensory-deprivation bath.
Now. Compare that to a 5-10 minute walk from your house. How many ballets? Islamic Cultural Center? Rock climbing? Boat rentals? Malayasian food? A pediatric urologist?
So, starting at 100, it is likely that your walkability is about 34. Most places are around that. It’s not really bad, it’s just scaled against places that are very very walkable. It kinds make me think, well, look at all the cool things we could have in our neighborhoods if we weren’t having to use the space to park all of those cars 
edit to add: And a Banksy mural!
And sounds wonderful!