Native 4k output instead of a crappy upscaler or a RetroTink which costs more alone than this Analogue product. N64's native composite is laggy and hideous on a flatscreen TV, you need something like this or a retrotink or a CRT to make the games look good. Even if the Analogue couldn't play ROMs off an SD card (it can, if Analogue's previous products are any indication), you could just stick a Summercart in it.

I personally am a ride-or-die CRT player for my retro consoles, but big CRTs are getting rarer and living rooms less accommodating. And N64's library has a ton of absolutely killer party games that are best experienced on a big TV with your friends, not a dark retro cave on a 20" CRT the way SNES RPGs are. If someone I knew wanted to go a "step past" emulation, I'd absolutely recommended this thing as the second shopping list priority. In order (imo):

Real N64, Real CRT, Summercart/ED64X7 (most authentic, and also cheapest if and only if you can source a CRT that fits your needs)

Analogue 3D, HDTV they already have

Real N64, RetroTink, Summercart/ED64X7 (more expensive than option 2 even if they already have the console and summercart lol)

Real N64, RetroTink or CRT, buying real copies of games at jacked-up collector prices