FS is quite useful for instrument practice but I don't think you will find it particularly helpful in the EARLY part of the PPL.
There are 3 specific reasons why it's not so great for learning basic FLYING (e.g. aircraft control and aerodynamics). This is true for ANY "game" type PC-simulator:
1. The flight dynamics (especially control responses) are considerably different from the real plane;
2. The lack of peripheral vision makes visual flying considerably more difficult than the real thing, causing you to use strange procedures to avoid crashing that you don't do in the real plane; and
3. The trim characteristics, specifically pitch, are very different from the real plane. Without getting too long-winded, joysticks are spring-loaded to a center position. This is grossly different from the way a yoke/stick operates (its neutral position moves back and forth when you trim to different speeds).
You may find it helpful for practicing PROCEDURES like going through checklists, generally familiarizing yourself with the kinds of systems in the plane, etc. You could get a similar benefit through "chair flying" with an instrument panel diagram or poster in front of you.
It is also good for practicing NAVIGATING, i.e. plotting a course, finding checkpoints, compensating for wind drift, etc.