Reading the terms of your reservation is important!
While you’re only due 50% back with a strict cancellation policy, it would still be worth communicating with the host. I have a strict policy but will refund any nights I’m able to re-book - it’s up to each host but some will do this.
Keep in mind that Airbnb hosts are individuals, not part of a corporation. Hotels can absorb last minute cancellations with all the other rooms they have, but for many of us running a single listing, a cancellation means the loss of a significant portion of our monthly income. Strict listings aren’t willing to run as much risk - book them and get your own travel insurance to cover cancellations, please don’t expect to take it out of your host’s pocket.