Yes and No.
I have 16GB for future proofing and because I occasionally edit video.
However, I absolutely get no benefit for gaming even with a few other programs running.
*Your 98% usage concerns me. Running CSGO and those other programs shouldn't be using all 8GB. There's either a memory leak issue with one of the programs, or Windows itself isn't properly closing unneeded programs to free up space.
You didn't mention GOOGLE CHROME. Web browsers and Chrome in particular can often use a lot of memory.
So...
Try:
a) REBOOT, and
b) Play CSGO with Task manager running in the background
Exit later and see what your maximum ram usage was.
(Windows itself can drop below 1GB usage if the game needs more and CSGO isn't incredibly...