Edit: what @Rat_au_van and @iansilversides said!
Hey Paul! 
So this is my understanding, being just a Monzo user:
There are limits on Monzo, just like any other current account - outbound is mostly around cash withdrawal limits (there’s a limit per day and over a 30 day period), with a higher limit of around 10k for bank transfers each day. For inbound, I think it’s unlimited for inbound bank transfer, however there are some limits for features which are Monzo specific (or rare to find in other banks) such as adding money via card* or payments by Monzo.me. I’m not sure if you can see the details before you get your card, but limits and full info should be available under settings (the cog icon) in the Account tab.
A point to note: while there are absolute limits, some folk are seeing anti-fraud measures kick in if they transfer large or unusual amounts from overseas or from other people. We can’t really discuss that on here, but it’ll be similar to checks in other banks, so Monzo shouldn’t be unique…
I think this is standard. I’m yet to meet someone who positively loves the video. (Actually, I’m keen to know whether this is checked and deleted or if it remains “on file”, but I digress…)
Some people have reported needing additional checks, but I think this happens before you get your card…
Hope this helps! 
*Inbound payments by card are reported to be being phased out for new customers, so if they still exist for you there will be a limit - they cost Monzo quite a bit of money.