Having more than 50 pies would be useful, as keeping instruments in a pie is a great way of tracking investment progress & return across your chosen category for that particular group of shares.
It’s easy to hit the 50 pie limit, especially when splitting pies with the maximum 50 slices into multiple pies to achieve a lower minimum investment cost, to help autoinvest of received dividends work sooner when the values of held shares isn’t huge and/or dividend yields are on the lower side.
EDIT: Typos 