I think the idea is - why even have memory if some is not used?
Your macOS takes care of all that for you -- and that's a Good Thing™
Yes exactly, that is most likely how it is suppose to be.
But the full use of RAM memory has sometimes got me wondering if that is the reason why my macBook Pro has been slow at times, meaning since it is already using all RAM for certain things maybe there is some process that doesnt get to use any RAM since there isnt any more availible RAM to use and hence its getting slow?
Just a thought?