Fix it or sell it?

Hello everyone

I just got this bike for free.
I think its a 2016 giant scr plus?

Needs tires and a regular tune
Should I upgrade the parts on this bike?

Or sell it and get something else? Cause it would cost around minimum $200 to fix it up or i can sell it for 300ish and add 200 towards a new bike for around 500 to 550 dollar different bike?

I have been a MTB rider only and want to start road biking.

Also this is a Small and I am 175cm so I think it will fit well?

Thanks !