Looking at it in D&D terms which the initial Final Fantasy was based, technically hit points represent your ability to turn aside otherwise fatal blows and make them less damaging. Your constitution (vitality is usually the stat to go by in FF) is how tough you are.

That being said in D&D, much like in FF, the system breaks down at high levels, especially since FF tends to have hideously overpowered spells that your characters can eventually shrug off.

For example, a Nuclear Missile in D&D terms is statted to do 16d8 damage, essentially 16 8-sided dice worth of damage. The average on that is 72, which is easily survivable by a lot of moderate-level characters.

Kind of like how, for example, Super Nova takes off a good chunk of your hit points instead of just vaporizing you. It doesn't seem plausible.

Oh right. Topic.

If we're talking exact FF game mechanics and I started at level 1, that'd imply I'd have enough training to use whatever weapons. So I would definitely go out and slaughter imps and take their money. Getting stronger and getting money without having to do some tedious work? Definitely. Plus if I still had a house I could rest for free and not have to pay inn fees, thus giving me more money for better equipment.