The fact that I can see all my transactions, automatically categorised, in an app that is much prettier, full-featured and simple than the crap that Halifax put out, is brilliant.
Combine that with a simple setup process, never having to interact with humans or call centres, and add tha bility to automatically save, interact with IFTTT etc and you have a very compelling package and I hope they continue to do well
Many people would argue this is a tech company's biggest flaw.
I can understand "never being able to" being a flaw. But if I can get my stuff done without talking to someone then that is brilliant. I don't have to go out of my way to go somewhere, I don't have to bother with a bad phone reception, I don't have to wait in a line for it to be my turn. I just do the things I need to do when it is convenient for me.
If I want to open a savings "pot" (Monzo version of a savings account). Then I can do it on the bus on the way to work. I don't have to take time off to go to a branch, or prove I am me on a phone call etc. I just use the app, and it's all done.
I have to say the best thing about Monzo is their customer service, it's really fantastic compared to other banks. I have other problems with them though - I won't use them with their 50p per day overdraft charge, even if you only go slightly into it; this persecutes poor people - it's much fairer to charge a flat percentage.