I installed Ignited via SideStore. No Jailbreaking necessary. Not computer tether. SideStore can renew the side loaded emulator every 7 days when on WiFi. The iPhone is perfect for DS emulation with a stylus.
(Ignited is a fork of Delta with more options, and SideStore is a fork of AltStore, with no computer tether needed)
Can confirm. I played so many games on DRaStic over the last few years. Zero issues.
Of course, some games are not well suited to a full touch screen, especially if they require quick coordination of both stylus and D-Pad. They are relatively few though - most games work great.