"Fake it 'til you make it" is a sure way to build a reputation... possibly a very bad one. In a day when the internet offers a permanent record of your exploits, a little far-sightedness and humility can go VERY far.
I have been telling people for 2 full decades that if I had it to do over, I would merely work at a rental house to start. That would have been 1980 had I done it, though a took a less intelligent route; it's even more true today.
There are DPs and then there are DPs. Which do you aspire to be ? Another dude with a camera who makes a couple bucks, or the next Roger Deakins ?
Digital and DSLRs have created an explosion of interest in cinematography as a career. You can "just do it" and call yourself a DP, but unless you have phenomenal talent ( a gift which cannot be learned or faked) or phenomenal hustle ( and that can work for some ), you are unlikley to rise above unnoticed projects... even if you manage to make a living at it.
If your goal is network TV or studio pictures, it's 100% who you know followed by what you know. The ONLY way to get that remains knowing real, working ACs, then DPs, and getting on set with a variety of them. The easiset way to do that is to be a good rental house employee.
Rental houses provide a job and a paid education in both real film gear and how it is treated and used, as well as connections to people working on real projects.
In my humble opinion, it's a no brainer... as long as you are at a good rental house that serves big clients.