I like using real games too, but it sure is nice having the flash cart option -- not to mention the perpetual worry of losing your saved game on a real cart with a vintage battery (I've replaced one or two, but don't really feel comfortable soldering). It's kept me from spending substantial cash on some really stinky games, like Traysia.
The main thing I miss is the manual; I hate going into a game not knowing what I'm supposed to know, as sometimes it makes a
huge difference and walkthroughs (or even the README files with translated ROMs) give too much away. I'd gladly pay a reasonable fee for nice manuals of translated games sold ŕ la carte, i.e. without the cart(e).