Just my 2cents, but I suspect the reason they front load so many charges is that a lot of people both employers/freelancers use freelancer for the initial connection and then move to paypal or similar for ongoing work.
Freelancer lets you establish trust between parties so to speak and then after that there isn't that much of an incentive to carry on using it if you're dealing with the same person.
This is exactly what I do/did. Making initial contact over Freelancer, payments over wire/skrill. I look only for crème de la crème clients (as funny as it sounds over those sites) and it is maybe one out of 100 hit. I have several recurring clients which i charge $50/hour and recently bumped price to $100/hour. For 3rd world country where I live, thats surreal money.
patio has very good point, and I'm looking to get off the FL bandwagon as soon as possible and switch to more prosperous/lucrative opportunities.
I talk as someone who's been there and done it. Perhaps I'm just picky with who I work for, but typically I do the initial job and then move to paypal, I've not had anyone not pay me yet for my work.
Freelancer lets you establish trust between parties so to speak and then after that there isn't that much of an incentive to carry on using it if you're dealing with the same person.