If Librem 5 wants to be appealing to non tech savvy potential customers and purism will be providing the accompanied store for Librem users, people will expect a watertight solution for mobile banking. I totally agree developers should focus on the priority list. In order to end the discussion whether or not online banking will be working of the bat, I can imagine it is not to much trouble for those having access to a dev kit to collectively log into their own banking account, doing a quick check and report back if they succeeded (+name bank), especially when it comes to European banks due to the very restricting new legislation on that continent. Like willing people like @maximilian is doing in his app testing thread, I presume there are quite a few others with dev kits willing to do a 5 minute test, it would be interesting to see what they will come up with.
Proving easy access to online banking will most definitely reassure potential customers like myself who are into the Purism /Librem philosophy and concept in buying but are still on the fence about pre-ordering one. Current most heard cons in the decision making process like being more ‘expensive’, ‘bulkier’, etc compared to mainstream smartphones providing x number of RAM compared to ‘only 3GB RAM’ arguments will then turn out to be almost non-existent.
Edit 1: Added link to @maximilian 's thread
Edit 2:
For further discussion regarding online banking apps and not hijacking this thread I’d like to take this over to Librem 5 - online banking app and other m.mobile websites