I like the idea for standard encounters but at the very least it would need tweaks for other encounters.
I had one session that involved a huge battle that lasted well over 100 rounds. Often there would be "spend 4 rounds to get across the field" or "everyone roll 20 times, tell me how many...
I need some low-level encounter ideas for a feast/party.
For my next session, I anticipate about half the time spent fighting the BBEG and the other half with the town celebrating victory. I'd like to come up with some meaningful encounters or have some half-prepared encounters ready depending...