Here are some admittedly random thoughts on the subject:
It’s possible for a guest to link the Airbnb accounts of any other guests to a reservation, but guests rarely do this, and in most cases, not all guests on a reservation have Airbnb accounts. I believe the only advantage to it is that the host review of the guests will be tied to all guest profiles. Ideally, linking a guest to a reservation would allow them to communicate with the host through the messaging system and also be copied on all communication from the host, but that wasn’t the case about a year ago.
Some hosts put in their house rules that all guest names must be provided and they have success with that strategy.
Some hosts put in their house rules that the guest must sign a separate rental contract and that contract requires all guest names (and other personal info like age and home address). This seems to be more common with hosts that list on several platforms.
Some hosts say that their insurance company requires it, but in my research of STR insurance in Nov/Dec 2018, not one insurer I contacted required it, so I question the truthfulness of this. (If anybody here knows, I’d love to know what companies requires it).
Some local governments require names and/or photocopied IDs of all guests. I’ve found this to be commonplace in Europe.
If you require all guests names, but your local government does not, having Instant Book turned on is a bad idea since there’s no way to ensure names are provided before booking and the host would have to cancel the reservation if the guest doesn’t provide the info after booking. On the other hand, if your local government requires the info, then you can simply deny entry until it’s provided. Airbnb must back you up if you are complying with the law.
Getting a list of all guest names is probably another deterrent against bad guests (just like Airbnb verified ID), but if you aren’t also checking the IDs of all guests, then how do you know they aren’t made-up aliases?
If you are thinking about checking IDs of guests, do NOT make copies of IDs unless your local government requires it and you follow the information handling guidelines of that government. The criminal or civil penalties for failure to protect personal information can be severe.
Historically, Airbnb hasn’t been very supportive of hosts with booking requirements that are more strict than Airbnb’s own policies, and if there’s a problem, you need to be prepared for whatever outcome is decided by a random poorly-trained customer service agent.