I don't know for other users, but when I edit documents on Adobe tools i press control-s every two or three actions to update my current project on disk
find very useful too the reminder to save when i exit the program (i know, here there is the "last" button, but i see the usage is quite deprecated)
and I always have a rollback folder with several previous version of the document

The fact to have to manually overwrite the current vMix project (to me) seems very slow and cause of potential mistakes

so, in my very personal opinion, i feel really very top maxi useful to have the same approach here
just my opinion, may be i am wrong, but... may be i am right :-)
ciao to all.

1st of all thank you for your answer
i was not aware of this function, and I have tested immediately
unfortunately the "SavePreset" function, assigned to one of my APCmini device actually open the SAVE AS window, and does not update the current project as the CTRL/CMD-S function does

better but not perfect
but, again, thank you