Accepting all recommended changes (without review) for license records which are already set up and configured as you want them is not something I would normally suggest doing without a specific reason for doing that - as you note, it can be damaging. That is a key reason why FlexNet generally won't apply recommended changes automatically: it doesn't want to assume to know more about your licenses than you know. Accepting all recommended changes may be helpful in situations where there is broad uncertainty about how license records in FlexNet have been set up and you're wanting to get back to a clean baseline to start refinement from, or in a situation where records are just being set up for the first time.
As @JohnTech has described, the Recommended License Changes page will identify differences between the way that you have your license records set up and modeled compared to the default license settings suggested in the PURL/SKU Libraries. The settings from the libraries are useful to use as a starting point or if you are unsure what settings to use for a license, but shouldn't be universally taken as the only possible way to model your entitlements. There are plenty of good reasons why you may have different settings configured on your licenses compared to the defaults (e.g. if you have non-default terms with in your license, or the way you model your organizational data is different from what the defaults expect). Where you have non-default settings selected like this, you would not normally want to accept every recommended change to override your settings.
(Did my reply solve the question? Click "ACCEPT AS SOLUTION" to help others find answers faster. Liked something? Click "KUDO". Anything expressed here is my own view and not necessarily that of my employer, Flexera.)
