I’m not the person you replied to, but it’s great for telling you why the check engine light is on. If you’re somewhere that requires emission testing: you can diagnose if you have an exhaust leak, bad O2 sensor, clogged catalytic converter, etc. Besides that: its good just to know if the check engine light can be safely ignored.
If you hate stock Android, definitely try Graphene. It doesn’t come with preinstalled bullshit and let’s you run your banking and other shitty apps in a different user profile. Google Play Store and Services are completely optional. You get nearly full control without the negatives associated with rooting.