hiyaCFW for emulation

hiyaCFW is just for if you want to have the official Nintendo DSi Menu running from SD so you can install other DSiWare, homebrew, forwarders, etc. It's also required if you want to use IR carts with nds-bootstrap since only the DSi Menu is able to correctly initialize those carts at the moment and a few DSiWare don't work from Unlaunch (which is how TWiLight Menu++ launches them) so you need hiya to run them, but other than those few things TWiLight Menu++ is better than the stock menu in most ways so there's not too much reason to use hiya unless you really like the stock menu.

 

It is a very convenient entrypoint, however if you really wanted to it's optional too (since with a fair amount of effort you could have installed the twilightmenu++ forwarder, or even the actual emulators, directly to internal storage)