The difference maist folk will feel is how the bike runs at the lower revs, particluarly if yer buggerin aboot in town or traffic. Yer right the ratio isnae that much different percentage wise tae rpm/speed but it definitely smooths oot the low speed/low revs stutterin the standard 16/40 gives.
Aye its a bitty nippier awa frae the lights but the benfefit is nae awe aboot speed.
Ultimate top end disnae matter a scroat in the real road ridin world.