The need to fill up more space-
I have always tried to play the organ percussively and sparingly, mainly so I don’t get in the way of the guitarist or soloist, and maybe so I don’t burn out on long chords.
Recently, I played a trio gig with no guitar player, and it sounded like there was something huge missing in our sound. On the second set, I played longer chords and bass notes, and it filled in nicely. It felt strange to play that way, but it really filled in that hole.