Again, the difference might be small but, I've thought playing seated in a modified classical position made the change to playing while standing easier, i.e., the guitar was directly in front of me, seated or standing. The position of the guitar relative to my body barely changed. YMMV.
"It takes a lot of devotion and work, or maybe I should say play, because if you love it, that's what it amounts to. I haven't found any shortcuts, and I've been looking for a long time."
-- Chet Atkins
-- Chet Atkins