Why does a value reappear in a Calc cell when its last digit is deleted?

A cell in LibreOffice (25.8.4.2) Calc contains a value, let’s say the number ‘123’.
With my cursor to the right (at the end of the number), I click Backspace and it becomes ‘12’. Backspace again, and it becomes ‘1’, then once more … and what I see is not an empty cell but ‘123’ again, as if I had not deleted it.
But if I hit Return now, the cell is empty, so it’s a phantom.
A similar thing happens if I start from the left and hit Delete repeatedly (123 -Del-> 23 → 3 → 123).

If this is intended to be a feature, what is the motivation?
Do people want it?
Was there a discussion about it among that developers somewhere that I can read?

It is called Autoinput. Turn it off if you don’t want it.