Any currency that aren't MW cores are kind of useless and plentiful, except maybe Planetary Mats.

The problem with Destiny's economy doesn't come from Bungie, imo. I know this will sound like utter garbage but time and time again, it's been shown that players just don't enjoy running low on mats or other currency.

Strange Coins, Motes of Light, Planetary Mats, Masterwork Cores, Legendary Marks/Shards have all been in a spot where they were so common that everything might as well have been free, thus making them useless. Or they've been perceived as being too rare, making it more of an annoyance that you can't frequently buy or upgrade what you want.

I've played many RPGs and only a few MMOs and when people say there are other games that do economy better than Destiny, I just don't see it. They all fall into the same "trap." Currency eventually becomes too commonplace and loses meaning and then they scale it back, "artificially" slowing down progress.

That's not to say Bungie hasn't made some dumbass decisions regarding their economy. Crucible/Vanguard marks being weekly capped, the current implementation of mods etc. But for the most part, currency isn't something players like to manage. So most devs just put it in there to give the illusion that the game has a deep economy system but more often than not could simply not exist and nothing would change.