Cosmic Exploration is CASUAL content with a pinch of midcore

[Minali]

when it costs you millions of gil to penta meld yes it's tryharding.

There is still the point that you don't need to pentameld for any of this though, it just makes things more convenient and allows for some optimizing for this specific kind of content, to my knowledge. (It's much more important for regular endgame gathering and crafting.)

You might not be aware if you're not gathering or crafting much, but gear you buy for scrips from Rowena's vendors cannot be overmelded. It's impossible to put more materia into these than the guaranteed slots they give you and depending on the piece of gear that's either one or two pieces of materia. So when people say they did this with scrip gear, it automatically means they did this without pentamelding said scrip gear.