You can extend memory and probably should leave it on

First of all, the most important thing I see is that in synthetic tests, there is no speed difference in RAM and storage, whether on or off.

This actually allows more applications to pick up where they left off. When the application is not used for a long time and new applications are opened, it is transferred from RAM to storage. When you return to the application, you will continue from the page, section etc. where you left off.

Turning this feature off will allow fewer apps to pick up where they left off. There is no change in the opening speed because it is still being started from storage. Because it was closed because it was not used and the place you left was transferred to storage. It does not boot as fast as it boots from RAM.

If you have enough free space on your phone, it will take a long time for the storage to degrade and you will most likely not be able to reach that level. But if your phone is too full, this wear will be faster. Because there will be less space in the phone's hand to distribute and balance the damage.

So, you need to consider the pros and cons and then decide. My phone is half empty so I leave it on as it will wear out slower.