Thanks for the correction - it appears I had downloaded old T&Cs.
I’ll compare it to my old company that went into liquidation instead then - we were FCA regulated and held a client account. It was around 4 months for the return of finances to those who had money in that account. I’m not comparing the businesses, I’m comparing the process of insolvency - it takes time, and the bigger/more complex the business, the longer it’ll take.
Okay, so we’ve got something to compare it to - this is good!
Overall, you see a ‘return’ of 2.3 x what you put in. However, let’s compare Monzo in exactly the same way you’ve compared Amex (as an example, the taxi credit is £10 per month rather than all in one go).
1% interest gives you a £20 return per year when maxed out.
1 free deposit per month, gives you £12 per year.
£400 foreign withdrawals is £200 more than standard, so that’s a £2400 increase per year - netting you a whopping £72 value.
You get 15% off plant and pot orders over £50 - £7.50
£15 off HelloFresh for 4 boxes - £60
50% off 6 bottles of wine from Naked Wines - £24.99
20% off Babylon Health - £29.80
25% off Fiit TV - £30
50% off a Basuu Premium Membership - £29.99
Total Annual Value: £286.28
Total Annual Cost: £60
That’s a 4.7 x value compared to the cost of Plus, in the first year.
What I’m trying to get at is that the value is dependent on your personal situations. I look at the Amex Platinum offers and see less than £570 value per year. Many of the ‘benefits’ require you to go and spend more money elsewhere with another party / on another thing just to get the benefit (30K rewards in your first year if you spend £4k within 6 months). Monzo’s main offering is to help you manage finances - the other offers are sweeteners, in excess of the main offering. Amex’s main offering is to get you to spend money, to generate them money (all of those benefits generate them revenue from their partners).
FWIW, I’ve already got my value from plus by taking up the HelloFresh offers. Heck, I could cut my losses after 3 months and only spend £5 to get £60 in value. I won’t though, as I continue to get non-financial gain through software features. In 12 months, I will re-evaluate what’s on offer - for now, I’m happy - if Monzo rests on this as their ‘final’ offering, then in 12 months I too may be looking for “the value”, but equally I may also want to learn a new language, spruce up my garden, and continue to get £20 interest (at which point my second year has value too) - who knows 
.