The once-only crap is just an end-run around the Superlink patent for a *reusable* link.
I always remove my chain for cleaning and lubing.

Take a close look at a Powerlock and a Powerlink side-by-side, and you can see the tiny raised area they added just to make it difficult to disassemble.
The MLP-1 pops it apart easily, and also makes opening Powerlinks easier.
I just put on a new SRAM 10s chain today, and routed around the wrong side of the tab inside the RD cage.