The deletion of the scan logs in the settings isn't so much a deletion but a paring down of logs, "Delete scan logs older than" X days. You can limit the some (of some of the logs) in the same group of settings, I have mine set at 64KB.
But in all honest the size of these text logs are small beer in terms of modern large hard drives, if you need to do that to save space you are in line for a new HDD.
I have never been much of a fan, so it is rare that I even look at this other than to confirm/test and it is working for me.