Still use the language bios switch. I installed a GCloader 2 weeks ago along with a switch because the issue with out of region MC's still exists. I had a JP game format a US formatted card, even though I was told Swiss patches that out now.
From what I saw and tested, it does, yet not with all games. A quick test to see this happen without any formatting is to create a USA Rouge Squadron II save on a US formatted card, change the bios to JP and boot the game. The save will load, yet if you reset the console, the game will complain that the MC needs to be formatted. Change back to a US bios and it's fine again.
Swiss loads any iso, regardless of the console bios used and also patches in JP fonts for games like Wario World, if booted on a US bios, as with modchips like the Xeno the text would be garbled characters.