It’s a bit off topic, but there is a long history to their plans in this area.
Originally, Monzo did plan to support cheque imaging. They publicly announced this here on the community and, I think, in a blog post - but it was made clear that they would only develop support for it once the Monzo current account had launched (at the time, this hadn’t happened and Monzo was a beta prepaid card).
It had been decided that cheque imaging was a fairly low-priority feature, so other new features were prioritised for development. Monzo realised that the window they had planned to launch in couldn’t be met, so they delayed the launch (to support cheque imaging, you have to join the ICS, which is the scheme that processes cheques, and you can only join at two dates during the year). Monzo realised that the original date they had been targeting was too optimistic, and publicity announced that delay, admitting that they also were not yet ready to commit to a new date. Most people therefore expected a delay of around a year.
During that time, other features gradually took priority and eventually Monzo reassessed whether it was worth developing support at all. They decided to cancel plans for cheque imaging indefinitely.
Some people on the community, including me, think this was a mistake and they should offer support for cheque imaging now that it’s becoming a standard feature at most other banks. Others argue that cheques themselves are outdated and Monzo shouldn’t waste time and money developing support for them.
So far, that’s the current situation and there has been no formal update from Monzo for a while (we assume this is because they haven’t changed their minds). In the meantime, I’d recommend using another bank for cheques (and also if you need to pay in cash).