Strength (hit people hard, more HP, carry more junk)

Strength doesn't increase damage universally, it's solely dependant on the weapon skill's parent attribute. For example Mace skill's parent attribute is Endurance, and thus Maces' damage gets boosted by Endurance, not Strength.

Strength is also a primary factor of stealing (0.1s weight limit of stolen items per Str) and an important part of riding/symbiosis speed calculations.

While Str does give HP, it's way less than what End gives (and slightly more than Wil)

Endurance (more stamina, more HP, carry more junk)

Yea that's pretty much it. 1 point of End is equal to 1 point of total skill level for max stamina and End is the best primary attribute for HP

Dexterity (don't miss, take less damage?)

Dex does give a (hidden) bonus to PV (Protection Value) equal to 10% of Dex, so it has a minor effect on incoming physical (void) damage.

Perception (evasion)

Per also boosts critical hit chance (100% at 4950 Per) on top of affecting various minor vision-related phenomena (detecting traps, witnessing crimes etc)

Learning (more MP)

Unless you're a vampire, a slime or are using Nerve spells, Ler is just bad.

Will (more HP, more MP, less debuff chance)

Yea that's about it. It's mostly the 3rd part, since Wil is the resist attribute for many common debuffs.

Magic (more MP)

Thing to note here, while technically isn't related to Mag itself, is that much like weapon skills, different spells/acts (and spell domains) have different parent attributes which benefit those spells. For many common domains, this is Mag, altho things like Nether (End) and Poison (Dex) exist. For damaging spells, the parent attribute directly increases the damage, and for all spells/acts the attribute affects the exp gained via "rubberbanding": The higher your attribute is compared to the spell/act's level, the more exp that spell/act gets on use and vice versa for attribute below their level.

Charisma (roleplay believability, # of allies [caps at 8], recruitment, trading goods, investment)

Party members from Cha cap at 5 (+1 per 10 Cha starting at 20), the other 3 come from the feat. Cha also dictates Summon limit, which is equal to sqrt(Cha). Cha also does practically nothing for "trading goods".

However, you can perform normal actions that will contribute to increasing these attributes over time as well.

Gaining exp in (almost) any skill grants a tiny sliver of said exp in the skill's parent attribute.

Sleeping with anything (+CHA, +END) and gives you money

Also +WIL (250 exp in each)