As someone who has that extra room, which I have made into an office, I say, if you can afford it, do it. Not only is it good for WFH, it makes a good hobby room/library for me.
I agree with you about WFH in the future, as well. When I can go back to an office, 1-2 WFH days a week is about what I want. That would be a bit of an uptick for me, since I normally would take 1-2 WFH days a month, but there's enough to like about it that I don't want to give up (getting the commute time back is nice sometimes), and I've gotten good enough at it to sustain it.
I agree with you about WFH in the future, as well. When I can go back to an office, 1-2 WFH days a week is about what I want. That would be a bit of an uptick for me, since I normally would take 1-2 WFH days a month, but there's enough to like about it that I don't want to give up (getting the commute time back is nice sometimes), and I've gotten good enough at it to sustain it.