In bad circumstances you don't want to lose all your payment infrastructure e.g. if paymill or stripe go out of business/have issues. That's why dealing with 2 parties may look odd but in the end it is worth the effort.
If you have problems paying the 50-100$ monthly fee, then your business is the problem. Not your payment partner.
(WireCard is a profitable, public credit-card processing bank, the chances that they go out of business is much lower than VC driven payment startups. See http://www.wirecard.com/investor-relations/ for details. They do CC-payments for Deutsche Telekom and Lufthansa. >11 Billion Euro/year)
Why should a scrappy startup pay an extra 50-100$ when it doesn't have to?
Why should a scrappy startup deal with the horrible paperwork of payment gateways on top of the horrible integration, when it doesn't have to?
You make no sense.