why do pros use mana immediately after leaving fountain / to leave fountain
i see scarra run out of fountain and then use W as Annie. I see
https://www.youtube.com/watch?v=AfQNGizBw3c
(whoever that guy is)
using Lucian's dash to dash out of fountain, even early game when it's cutting into mana a lot...
I'm curious why these people do this - their mana doesn't totally regen before they get into combat again... seems like a needless disadvantage.