Is it worth it?
Let me explain to you.
I've been with Vegas since version 7. I'm currently using version 12 pro. I've learned Resolve, currently using the 14 beta version, it's simply amazing. I hate to say that Vegas is going to become slowly irrelevant. Like you, when I was using Vegas 12 I thought I would just use Resolve to color correct. Nope. Resolve 14 is now a very capable editor and the sound editor is very good too.
Sorry, Vegas, not updating and frankly I think Vegas is going to go as Resolve is free and becomes more and more capable.
I strongly advise you to start learning Resolve, then learn Fusion that works hand to hand with it.
I know, It's breaking my heart, and I used to love vegas, and I still think the interface is amazing, but come on, Resolve is as good, better as far as color correction, and free!