Why is rook better than bishop?

I've always thought that only the queen is usually better than a bishop because a queen can move more freely.  Thanks for showing me that a rook can attack squares of either color!  So, I guess it also makes it something better than a bishop.  How about a pawn?  It can turn into a queen...

I assume it's because a rook can move straight ahead instead of diagonally. A lot of it is just point count though. A bishop can beat a rook especially if there are no open files

It honestly depends on the situation. For instance, I have sacked my rook for a queen/bishop check mate many of times. Not only that, if you have a winning position with the bishop, rather than the rook then the rook is less useful.