I also don't like the PT, but as far as QG not having the credits, individual Jedi are not rich, don't believe in personal possessions (could have credits for missions), was on Tatooine (a backwater, outer rim planet), and it was around 20 years prior to where the "basis" of EotE is "supposed" to be set.
A lot can happen in 20 years as far as tech is concerned.
I don't disagree but we are talking about the Outer Rim, and most probably the Colonies as well, so even if QG did have access to a Jedi slush fund (which is likely) a transfer of Cr just may not have been possible to do securely. If the PCs are in the Core I would go with electronic transfers, at least for above board transactions, but in the Rim and most of the Colonies I'd stick with cash or local banking establishments with electronic transfer being possible between world but time consuming because of the necessary verification, sort of like how bank transfers work now (if you've never sent money from one country to another from your bank it usually takes a few days for the banks to verify, which can be a pain,). It may also be impractical because it's nearly impossible to remain ahead of the curve when it comes to potential electronic theft, especially with potentially billions of technologically savvy cyber criminals and organizations trying to hack the systems. This would necessitate a hard currency system to ensure security.
As for advances in technology this is kind of a false comparison. Most of the tech in the SW universe is thousands of years old and is relatively stagnant, sort of like China before Western colonialism. They had had periods of great advancements then settled into a very long period of stagnation (at least technologically). Why this happened is a longer discussion but it's not important other than it being an example. So even though our technological development has grow exponentially that is no guarantee of future development.
I prefer to think that the Republic and later the Empire are in an equivalent stage of advancement but on a galactic scale, sort of a technological Dark Age where new developments are slow to emerge because old tech works well enough, if a bit inconvenient at times.