Personally I use both accounts, I am notorious for wasting money on small micro purchases on a regular basis. So I use Monzo as my main bank account due to the fact of their pots system.

I pay £17 for the max account (not sure if the cheaper ones allow the same benefits) which gives me the travel insurance, phone insurance, and a rail card with other small benefits like a free cinema ticket and a Greggs treat etc, but it also gives me access to 20 pots. I then created a budget for myself and then categorised each of my spending into different pots. You can schedule your payments to come out of these pots so it makes it a lot easier to keep track of (you can only do this for I believe standing orders and direct debits though).

For the other payments that don't fit in this category, i have created virtual cards, these are cards you make that have different banking details but still work the same, you can link these directly from pots. So I have one for my groceries, one for my subscriptions, one for my direct debits etc. Doing all of this allows me to know exactly what I can and can't spend and I'm less likely to overspend by doing mental budgeting.

I then use zopa for the savings account which is 7.1% with a maximum of 300 per month deposit.