not to argue but no the sega naomi pretty much is a souped up dreamcast the same goes for the namco 246 it is a ps2 motherboard in there that use's the same type memory cards as the home console there just beefed up a little.
98% of arcade games were made for 15K along with alot of the sega title's arcade games and also why alot of the games for the dreamcast were the same thing as the arcade becuase in reality they were the same exact game running on the same hardware but uinstead of saying insert coin they changed it to free play or press start but the game itself is the same as the arcade version.
the dreamcast can display true 15K when put in 15K and when fed to a 15K moniotr there is no better display as it is in its native state that way and the exact way they were desighned for from the begining.
if you like show me a DC on your non 15K and I will show you mine on 15K.
dc games were out in the arcade first and then ported to the console and most of them were either 15K or a slim 25K like virtua fighter.
I also run mine on a nanao MS-26SU from an offical dedicated sega cab
Litttle nitpick; the Namco System 246 wasn't a souped up PS2 at all, it had identical specs.

The System 2
56 was the one with more ram.
However the Sega Dreamcast is different from teh PS2. The vast majority of PS2 games are built from a hardware level up for interlaced output. It takes extra effort to get progressive visuals to come out of the PS2. I'll admit I'm not exactly sure as to WHY, but I presume it comes at a processing cost or development complexity. The list of PS2 games that support 480p output is pretty short. So the vast majority of games are built for 15khz interlaced output.
The Dreamcast however is exclusively 480p in rendering, any signal has to be converted to interlaced. It was built using a PC oriented graphics chip and that's why nearly all of it's games support VGA output and many of the remainder can be patched for VGA output. The Dreamcast and all it's software was made and is rendered at 640x480, not a single game for the Dreamcast uses any other resolution other than 640x480 (A feat the PS2 doesn't even accomplish! A lot of games are at lower resolution). This stuff is best viewed on a progressive 31khz display. Try it on a 4:3 VGA CRT monitor. It's just
so damn pretty. It's best enjoyed progressively and seeing every pixel that the machine is rendering. Interlaced 15khz views lose data from the interlacing.