Sometimes the data in the history for entities gets messed up and then there is forever a discontinuity in the history data. It would be really nice to have a simple GUI based editor to be able to replace values in the history database to correct data issues. My big one right now is that sometimes the utility meter messes up on restart for my power monitor. This in turn messes up the electricity cost calculation I do which is frustrating and makes it unreliable.
It would also be handy if you could write history after the fact, one use case would be to enter data that is buffered in the source. Some energy data can be downloaded as hourly numbers for several months, a historical update could then be posted allowing HA to fill in the missing data. Another case could be the recalculation of a calculated value due to changes in the formula.
an other use case:
I get my energy readings via shelly 3EM, but my gas and water meter are just plain analog. no way to get a digital read out. So I would like to read the meter every other month and manually set the data into HA.
But you can easily do this. Just create a number helper and then but they values in.
With an utility sensor you even get monthly and daily and so on.
Depending on your gas counter valve you can automate it with an esp