Would also be a nice bonus feature if we could mark subscription transactions to get a notification prior to renewals

A variation on that use case is to track which card is on file with a payee. For example, my dentist has my Citi Double card. This is useful to track for a couple of reasons. Chase may create a bonus category for medical so I would like to know to call my dentist and give them my CFU card number.

Or if a card is compromised, it would be nice to have a list of everyone who charges that card (subscription or other).