Plumeria does allow you to get cards into discard pile. Energies for aqua patch or mega turbo, or as was mentioned in article regarding Darkrai ability. However I prefer draw support rather than discard your cards for one energy removal. Plus other ways to get cards into discard....ultra ball, sycamore, and rarely used psychic third eye (think that's its name).
You're on the right path here~
Remember people, discarding cards is not strictly a bad thing.
With Oranguru being one of our only draw options (post-rotation), discarding can actually help fix your hand.
A lot of decks interact with the discard pile.
I think the main problem with Plumeria is, it's effect is a sort of... "half-strategy."
The effect, while good, isn't always necessary.
A lot of the time, you can just discard with an Ultra Ball.
Sure, you can fetch this with Lele, but... you could also just fetch Skyla, and grab an Ultra-Ball.
Most of the time, using an Ultra Ball will help you out more.
But, based on the deck, I could see this being favored over Flare Grunt.
As
@Gengar master said; this could help with things like Archie.
The problem is, it's a supporter, so you wouldn't be able to Archie that turn anyways.
Though, that is also a strength of this card.
I can see this potentially replacing crushing hammers, to avoid feeding into a Garbodor.
But, you might end up discarding items just to play it... so, who knows...
Would work well in my
(WIP)Chandelure deck tho~
TL;DR It's an interesting tempo card, but it's niche is more-or-less filled already.