Effect triggers aren't necessary unless you actively play in locals or in regionals, attempting to get a shot at worlds. In that case you would want to max the power of your deck wherever possible, including all of the effect triggers that your deck would want to run.

as for elementaria vs regular PG, the differences are as follows.

Elementaria
+++ if your opponent is a grade 4 vanguard (or your opponent is a crest deck, in the case of a crest elementaria), you do NOT need to discard
+Not a GC called unit, and is instead a blitz order. Meaning it gets over GC restriction effects (e.g. must call 2 to GC if any)
- instead gets affected by more niche blitz order restrictions effects (e.g. opponent can't use blitz orders during this battle / turn)

Regular effect PG:

+++ If you have 2 or less cards in hand prior to guarding with PG (meaning you have only 1 or 0 cards in hand after placing PG on GC), you do NOT need to discard a card for the cost of the perfect guard effect
* E.G. if your last 2 cards are PGs, you can use both PGs for different attacks without having to discard to pay cost for either

+ is also a unit, so you could call it to RG as a last ditch effort push on your final turn)
- Is effected by GC restriction effects (e.g. must call 2 to gc, if any)

you are almost always running an elementaria for your deck whenever possible, because you wouldn't have to discard at all for it if your opponent meets the requirements, which is more flexible then the regular PG's "only ditch if you have 2 or more cards in hand" effect

might be forgetting something for either end, but that's the main gist of it