I would build whatever option you like better for your family. Ultimately, this is your house and no one knows what the future of AirBnB will be as cities experiment with different regulatory approaches.
I have a basement apartment that I rent on AirBnB. It is fully occupied year-round, I make good money, I'm a Superhost, and I've never had any guests complain about basementy-things ... and it is truly a basement with all the basement issues -- dark, small windows, low ceilings, noise from upstairs, etc. I agree that an above-ground unit might be "nicer," but I've had no trouble renting my space as is. In my experience, AirBnB demand is based more on your geographic area (city/region) and specific location (neighborhood, proximity to attractions/services) more than anything else. Beyond that, write your listing to let folks set expectations appropriately (e.g., it's a basement), communicate clearly and kindly, and create a cozy space that is welcoming to your guests. Provide some nice amenities -- quality bedding, snacks, supplies, etc., and you'll be good.