I feel like this issue is a bit confusing to me, partially because I've been able to accrue at least some wealth in-game but also spend it quickly on buying companion gifts on Odessan and then using crew missions to sell crafting supplies to make more money. But as many others have said, charging a fee on simple tasks like fast travelling is more a punishment than anything else, and effects new players disproportionately. For me, it's annoying but makes literally no difference, but for a new player I see ways for that to be a problem, especially at lower levels. Even my wife enjoys the benefit of me giving her credits, and she's still found the cost of travelling troublesome on occasions. Especially seeing as how we bought the perks to instantly recharge QT, now having to pay every time is really just annoying.
The biggest issue I see as needing a fix is cartel market having items that are grossly overpriced. I mean it's one thing when crafting supplies are sold for prices higher than they technically should cost, (which is also a great way for newer/casual players to actually gain some wealth like myself), but when some things in GTN are sold for several billion credits for no evident reason, that's kinda ridiculous.
Another issue to fix is the fact so many things simply don't use credits anymore. It's not something I've become wealthy or high enough level to really notice, but I can still tell that it exists. This game has a lot of different currencies and reaching the point where I actually care about them is becoming a nuisance.
As I'm starting to join the group of higher-level players with at least some in-game wealth, I'm starting to recognize how these issues effect new players more than others and realizing the true gap between people like myself and those who can actually afford to spend several billion credits on stuff.
These are just my personal observations as someone who really loves this game and has reached the point of now learning end-game content.