You will generally not see much of an improvement in games by upgrading from 4GB to 8GB. However, if you get "low memory" errors, then it is recommended that you do upgrade. I played Star Trek Online with my laptop from time to time with only 4GB of RAM and a Radeon HD 8850m with 2GB of dedicated VRAM, and from time to time I got those errors and in a few cases, may laptop froze. Upgrading to 8GB of RAM fixed that issue.
It is best to get a PS4 for games because games designed to for the PS4 will run on the PS4... unless it is a totally bugged game to begin with. A PS4 game released in 2020 will run on any PS4 no matter when it is purchased because the hardware remains the same. In the PC arena new hardware is always coming out and games are always pushing the performance envelop. While your current laptop may give you decent performance for most 2014 games, as the years progress, the hardware requirements will increase.