Whilst I feel tabs are great, the simple fact that everything is split evenly is annoying. If I buy a round of drinks but also get some food for myself I don’t want this food split as well. That’s as good an example I can think of off the top of my head.
Not sure how easy it would be to edit the amount you want added to the tab, rather than the full transaction amount.
Using the above example…
Transaction total - £32.57
My food - £12.99
Put in Tab - £19.58
Great for days out with friends where you have multiple transactions across multiple cards.