The monthly subscription is not a requirement. Even the rig purchase isn't a requirement to get swap rewards. 

Swap for rewards, use rewards to buy rig, mine, sell mined tokens for sol, buy pro... You could literally have everything for maybe $10 and the time spent swapping. 

Besides that, the pro is going to have a bunch of tools that help you make smarter decisions. 

I'm not sure how clear the picture is for most people, but what I'm seeing is an absolute paradigm shift.