Each element is tied to a certain enemy faction. and their shields is that element. using the element on them deals bonus damage and helps take down the shields much faster.
- Fallen - Arc damage, signified by blue shields
- Hive - Solar damage, signified by orange shields
- Vex - Void damage, signified by purple shields (exception: some Harpies have arc shields)
- Cabal - Solar damage, signified by orange shields
Most of the time you won't need the element to deal damage, but in a few rare cases I've noticed one area so far with Vex Harpies with Arc shields that take damage from Arc attacks, but resist all others (still do damage, just a lot less).
Your primary weapon will usually be Kinetic damage. Your special and heavy weapons can and should have an element. Preferably one of each element so you are prepared for any encounter.
To directly answer your question instead of quoting long winded and confusing reddit posts:
No, upping your light level will not make you more effective in terms of damage on content unless you were previously underlevelled for it, assuming the same weaponry. Your weapon reaches its maximum damage the moment you hit the same level as the enemy upon which you are firing (unless you're using severely underlevelled weapons, see below), and it will stay that way against all enemies you are of equal or higher level to. The only way to increase your DPS is by upping your weapon's attack or getting higher attack weaponry (or I guess unlocking certain armor mods, but that's besides the point).
Sidenote: This does NOT apply to abilities, just weaponry. Your abilities increase in damage as your light amount goes up.
You will, however, benefit from the better abilities that are on those pieces of equipment and the increased armor rating, which will allow you to survive better. You will also presumably have faster recharging abilities due to the higher level of stats on better gear.
The only way level applies to damage, then, is down scaling due to being underlevelled. If your level is below the level of the enemy you are fighting, you take sharp damage penalties, at four levels below you are not damaging the enemy at all (its level will show ??). There's also a damage penalty if your weapon's "internal level" is much higher than the enemy you are fighting, but that's rarely very useful information. It does, however, mean that you won't suddenly do worse against low level content just because YOU levelled up, if you're still using the same gun.
Best Answer
Summarizing data gleaned so far:
Approximately 80% of the difference between the values of the gear that is used. (See answer to #4 for more detail.)
Other stats may get a slight bump, to scale with the gear's quality, but the overall roll won't be substantially changed. Which stats see boosts, and by how much, hasn't been verified.
No.
Yes. The formula is roughly
N = O + ((I - O) * 0.8), where:Some sort of rounding is done when the formula does not put out a whole number value for N. The rounding logic that is used (or even if the rounding is predictable at all) has not yet been definitively verified.
The minimum boost is 1. Logically, this reduces the likelihood that "round down" is being used since that would require hard-coding the minimum. (Not really a big deal, but probably best to avoid if possible.)
Indeed, some players have reported "round up" being used while others report cases of "round down". This would make "round to nearest" seem to be the most likely candidate, but I personally have had mixed results and haven't been able to nail it down.
Further testing and input would certainly be appreciated.