I think every situation is different based on how many transient visitors/tourists come to your area, and what the hotels typically charge per night each season. That said, here is my scenario:
I purchased my estate sale 3BR house in Portland, ME for roughly $175K. If you're not familiar, Portland tends to get a TON of tourists during the summer but is a bit of a ghost town for visitors, with the exception of those passing through to ski areas. Real estate, strangely enough, is still relatively affordable, so this is the perfect formula for AirBnb. My house in question had a 420sq ft in-law apartment that was not legal, but was being rented for $400/mo to a relative. Before I purchased, my realtor and I sat down with the zoning office to make sure the 'non-conforming dwelling' could be converted into a legal apartment (the previous owners had converted their garage into this apartment in the early 80s and never got the proper permits).
Long story short is I completely gutted the apartment right after purchasing and converted it into a 'modern rustic' studio apartment. I did most of the work, with the exception of the full rewiring and replumbing. Total renovations cost me 20K. Since it went live on AirBnB in July 2016, it's had an occupancy rate of about 95%. The nightly rate ranges from $60 (Jan-Mar) to about $175 (summer weekends). Average nightly rate is probably about $120 for the year. This will provide me with an additional yearly income of about $25-28K after all taxes. I also invested in a Roku device and a WIFI signal booster so I can stream things in my own home (30 ft away) and still write off 100% of the apartment internet/cable, 50% Netflix, 50% Amazon Prime, 50% Hulu as a business expense.
My own commitment is very low. Average stay is about 3 nights, and since I work from home 4 days a week I can build the available rental days around when I'm home. Now that I've got a system down, it takes me about 30 minutes between stays to change all the towels and linens and to clean the place.
For me personally this has been a great investment. In addition to the extra income that I've been putting toward my primary home renovations, I should have my mortgage paid off in 3-4 years. Best part is I've added an extra $80-100K of value to my home by converting it from a single family to a 2 unit.
This scenario won't work for everyone, but AirBnb is a great way to get ahead if the situation is right