Theres no big public database in the sky for these things.. If I want to transfer to an asian account, I need to enter (at least once if stored) the iban.. If I need a payment made to my BVI consultancy company.. Or if you have to send money to an unnamed / numbered swiss account, the data must be entered.
Banking is not all public and open, as a uk person paying a uk entity may hope or expect.. Parts of the world is cobbled together with SWIFT, IBANS, BIC codes, Clearing banks, gateways, etc etc.. And Monzo has to feed into all of them, it can say "oh yeah, we cant send that money to X we are not in that database".
Day to day consumer high street spending in the UK is all well and good.. But the transition to being a bank, to operating in the global sphere, is not (IMO) going to be manageable, at least not nicely, with a phone interface. I am pretty confident that Monzo will handle that transition, I can imagine a highly slick Monzo tablet / desktop edition.. A place to edit and control creditors on record, to input long form transfer details, to present the data granularly in secondary swipes behind a nice timeline, a timeline you can slice to monthly where the start end balance is shown (giving me the reconcilable monthly statement I crave) and additions deductions all tally up in the period..
I have high hopes for the platform, but personally feel that platform will not be a viable one if a tiny handheld screen is all I have to access it with. If thats the case even as keen as I am, I wont been keeping it beyond dropping a grand in when going overseas to take the freebies (and hence cost them money with little benefit).