Confusion on the moving of the rook

I don't play that often but when I do I think I am pretty solid for my elo for example I just played this game which I really liked my performance nice swallow's tail mate at the end. Though a question I have is on move 19 I took the rook on f1 to e1 which the engine said was okay but the best move was taking the rook from a1 to e1 my question is what is the problem with this why is one the best move and the other is just "okay". Now this is a serious question because this happens often to me and I am just curious. Now to note I see the rook on a1 doing still nothing and I hear all this stuff on how it's good to get there pieces off the starting squares however if I do the rook from a1 to e1 it is just blocking my f1 rook from moving even though it was safe I didn't like the idea of it just sitting there with no squares to go to so I moved the f1 rook now it has squares to go to (not in that position but in I am thinking in the future) but that was my though process at that moment. Just curious if it is always generally better to move the rook on a1 to the open files rather than the one on h1 (castled f1), now could this deciding factor also depend on the position I think most likely but let me know.