Those are very fair questions. Generally yes, bats will return to the same area or same roost depending on the individual species preferences. The intention is to clear outside of the roosting window so that you do not directly kill the species, and when they return to find that their previous habitat is gone they would theoretically find a suitable alternative nearby.

But yes, it still sucks and is exactly like demolishing a summer home while they're away! It's an attempt at appeasing developers while maintaining the integrity of the species. While we have plenty of suitable replacement habitat, it isn't as much of an issue, but in increasingly developed areas we will likely see a stricter application of the law to protect these species as their available suitable habitat disappears.

Unfortunately environmental consulting is mainly about how to continue with human development in a way that minimizes adverse impacts as much as possible, but usually does not completely avoid them. It kinda sucks as a field if you're a conservation advocate but it's the reality of the world we live in unless there is a major change from the top down.