Yes, *most* of us, and our descendants should stay here as long as possible. It’s home, and we’ll probably never find another planet that’s quite as good for us to live on. We evolved here, just to suit the planet.
However, if it becomes *easy* to send a few people to other planets or other stars, either to visit or to live, then that’s good too.
What we shouldn’t do is to put too much of our resources into getting a few people off Earth. It’s not that urgent. And we shouldn’t think that because humanity might move somewhere else in the far future we don’t need to take care of Earth.
Agree with the other answers, we definitely need to take care of Earth for as long as possible! Although inevitably things will change to make that more difficult, right now and in the foreseeable future, getting us all off good old Earth to somewhere suitable is not feasible!