The OS uses spare RAM to cache frequently used files, the more spare RAM you have the more files it can cache and the faster it will run.
SSDs may be an order of magnitude faster than HDDs but memory is still an order of magnitude faster than SSD so you will get a reasonable gain from having lots of free memory.
It also makes it much easier if you ever want to have some VMs running (maybe to play with Linux or for an older version of Windows for some legacy apps).
The OS uses spare RAM to cache frequently used files, the more spare RAM you have the more files it can cache and the faster it will run.
SSDs may be an order of magnitude faster than HDDs but memory is still an order of magnitude faster than SSD so you will get a reasonable gain from having lots of free memory.
It also makes it much easier if you ever want to have some VMs running (maybe to play with Linux or for an older version of Windows for some legacy apps).