Since we're generating so many tokens off our commander we're utilizing them different ways like ramping with Prosperous Partnership, drawing cards and dishing more damage with Neyali, Suns' Vanguard, pumping Otharri equal to the number of creatures we have with Kemba's Banner, and pumping the team while protecting them with Nahiri's Resolve
Damage causes loss of life, so damage does trigger these effects
Those moments help preserve the childhood memories Marsh says he will never forget
Geosurge is still good enough to drop a big finisher (Inferno Titan, Wurmcoil Engine, maybe Balefire Dragon if you want to get cute) on turn 4, but that requires having both the enabler and the big creature in your starting 10 -- and remember that contemporary mono-red doesn't really have filtering or card draw
The combination of a fragile body and additional setup steps has mostly kept this card out of the top tier of Legacy, but its never far from that level