It might be - but take it with a grain of salt. Some data is better than no data but there are numerous flaws and even if it’s correct - could be deceptive. AirDNA in my experience is more accurate than Mashvisor. Keep in mind:
- the system is not great at telling whether the blocked day is a paid day or blocked by the owner
- some people only rent their properties during a part of the year and not full time
- AirDNA and Mashvisor rely on Airbnb data. For HomeAway and Booking.com they have to guess prices
Still, directionally, it can give you some sense how well the properties are doing on a high level.
The best way to find out - find someone who is doing it and see if they just tell you their numbers :)
A trick you could use: call property management firms, play damn, say you want to buy a condo and give it to them to manage and ask how much a property like that could generate in their opinion. They have a lot of data.