I agree with Colin. I’ve saved many sits, actually starting before home owners had the ability to see them. My main reason for saving/favouriting them is so that I am notified when the home owner posts a sit.
However, in my opinion, it doesn’t really work the other way around. Even if I have the dates set as “available”, I may not be prepared to go to a sit when a home owner sends an invite. Almost all of our sits are planned well in advance and are made as part of a longer trip to a specific area. It’s rare that I would be able to accept a sit I was invited to.
The fact that a home owner can now see who has favourited their sit might be useful information, but it’s unlikely that you could rely on it as a method of finding a potential sitter.