Daedalus started as a proof of concept.
It took a long time before Super mario 64 became playable.
I don't call an emu that needs a lot of different speedhacks and other optimizations to run a game a "playable" emulator.
It's still more of a POC then a fully working one.
It just happens that the Daedalus devs where able to push the PSP to the extreme.
Well that and the release of the 2000 PSP's with 64MB of RAM also helped a lot.
PS1 is easier to emulate then the N64 tho.
Seeing that the DSTwo is hardware wise exactly the same as the Dingoo the two can emulate the
PS1
DSTwo is only able to emulate the PS1 in DSTwo linux.