Are you talking about Ability Points (STR/DEX/INT/LUK) or Skill Points (for skills, which differ by class)?
For Ability Points, there is no reason to do anything other than auto-assign. Putting AP in any stat except your class's primary will make your character weaker, and therefore it's very good that the game makes it harder to make such a mistake. I don't see how it would be "forgiving" to let people easily assign multiple points to a sub-optimal stat.
For Skill Points, the UI does allow you to assign as many as you want at once. It hardly matters anyway, since all classes except Beast Tamer get enough SP to max all their skills by the time they're level 140.
The drop rate for armor is very low from solo voyages. It's not really worth going for. You'd do much better to use armor from Hilla, Von Leon, or Cygnus, as precursors to CRA.
The reason most people keep doing Commerci is for Denaro for buying certain accessories from the NPC.
