You can try to have one magic board that will make surfing fun in every type of condition… but truth be told; you will never find that magic board.
Let’s say you shortboard- chances are, most days its going to be around waist high (if we’re lucky, eh East Coasters). Your typical grovler is going to make these waves fun for carving some turns and maybe pulling off the occasional air. But when the bigger days come along, chances are you are going to be outgunned on your groveler. Nothing is worse than paddling hard for a set wave, standing up, and eating it hard because your board didn’t have enough rocker or volume to make the late drop. In this situation, a step up would make your surfing a whole lot more enjoyable.
What about those smaller days, where it is perfectly clean with offshore winds and weak, long lines. You aren’t going to be able to catch anything on your shortboard, so a longboard or SUP would be ideal.
And long boarders, you know you hate riding such massive boards when its firing. Go for something that’s fairly long, but gives you the ability to duck dive, while still getting into the wave nice and early.
Of course you can get away with riding one board, but you will have a lot more fun with the proper board for the occasion.