Rent is better for the income, but not as much fun. I like getting into C2 so I don't have to play as much (and risk dropping into dreaded gold with attribute loss :D )
I also prefer to play to be on top of the metas as it could give tips on what cards are in demand to invest in.
Yeah, this is very important for investors to know.
The other thing with playing is that it does help feed the ecosystem - especially when people like yourself are invested and still playing - the knowledge share and "lead by example" matters in my opinion. I wish more old timers would add their views on how it is going economically, as well as through the meta changes.