Well, there are no requirements to have monzo current account opened. In reality, all minuses of prepaid card go away, like downtimes caused by third party companies, prepaid card sometimes rejected and lack of FSCS cover and you get some bonuses like bank transfers (which you may or may not use, up to you).
What aspect of current account could stop you from using Monzo’s current account in the same way that you use prepaid card now? Even tops ups will remain as functionality, if I remember correctly. So you can have your current account in ‘boring’ bank with your income, and current account with Monzo for spending, same thing really, right?
Having more than one card, virtual cards and spare backups had been discussed in various topics though - but all of them in context of having them on current account eventually.
I’m on that other side 
, prepaid card cannot go away fast enough, because debit card and current account is so much more functional, not to mention doing all processing in house (I trust Monzo to do a better job than third party companies in terms of bugs and downtimes).