I 100% every single game I play, not only VNs lol be it otoge, BL or any other genre. I'm a completionist at my core! If I pay for the whole game, I wanna play the whole game ;b
I believe playing all routes can give you a new perspective about certain characters or the plot. One thing I enjoy is characters who've been in love with the MC in all routes (it's very cute!!) or learning more about the LIs relationships with each other during a different route, like sibling-type dynamics or rivalry. Seeing how my favorite LI behaves in other routes is part of the fun! Haha