+1 for casting, +1 for to hit, +1 for dodge, +1 for damage (I think), +1 for perception checks, +1 for... yeah, lucky probably isn't that strong compared to buying a few specific skills.
from a stat gamer pov, three 'lucky' gives +3 to any roll, body, mind, or spirit based. but since the system automatically uses either the stat itself, or stat/2 for most roll modifiers, if you just took the improved body/mind/spirit talents instead you would get a +3 or +6 to every roll, plus the other benefits of higher stats (more hp, more ep, higher pleasure threshold).
the only rolls that might make luck worthwhile are the secret rolls unrelated to your stats, such as loot tables, encounter charts, or other information we don't see.
p.s. what stat is related to stealth? >.> or is it varied like perception too?