CPA Leads Generation (Fiverr Services)

Hi guys!
I'm new in the world of cpa marketing.
I started buying media on Push House and it generates some clicks and some leads.
I saw fiverr services of some experts they say that they can optimize campaigns and generate more leads to your cpa offers.

I want to ask you, does anyone have experiance in buying that kind of services and what do you think of this ?

Thanks in advance!
Kind regards!

It requires such a low effort to steal your winning campaigns and run the same offers, that even if I knew they are really professionals (which I doubt), I wouldn't let them anywhere near my campaigns.