Hello dilan,
Yes, GTA V can be purchased on Steam, the PC requirements are listed on Steam as well. If you check Epic Games each week, you might can catch GTA V for free.
The advantages of a pc over consoles is that you can have higher end hardware to run at higher resolutions with the highest detail settings and with higher frames per second. PC is superior over consoles.
If you do some research, I'm sure you'll find the answers to the questions you have, but feel free to ask any you may have.
