Never read the Tasmota documentation? It clearly states: if it ain’t broken, don’t update.
That is probably the reason the Tasmota integration never implemented an update sensor.
First of all, show respect, like I am doing in my response.
I have read the documentation many times and I agree with you, do not upgrade if works, but can you tell me where in my request I have said autoupdate? I’ve said, only a notification of a newer firmware when available and if they want, then in a future maybe include the upgrade from HA if possible.
You never know, you might be waiting for a new version due to a bug or a new feature or sensor supported… who knows.