I would assume only the ones that use the netdimm would work with triforce and chihiro, so both Chihiro and Triforce Type 1 games only.
Yeah, well, obviously. Non-type 1 boards [
Type 3] have their own built in memory [like an integrated DIMM], which can also be netbooted, so no need for either a NetDIMM or a flash cartridge.
Probably wouldn't need the battery that the netdimm has, so previously loaded game would not be erased if the board has not been booted in a few days, and one less battery to worry about
Having the last flashed game in memory sure is convenient, but my Pi + NetDIMM flash times are by no means a deal breaker. Besides, this is arcade, not a MAME cab. You're supposed to play one game, not swap roms every fifteen seconds like some emu-YouTube yell-at-the-screen brat. I can certainly wait a minute or two. Triforce and Chihiro games can be quite large, and they still flash pretty quickly. If I can survive swapping CPS3 games every once in a while, this is not a problem, at all.
Ability to select bios from the game select screen (like neo sd)
What do you mean? How can you select BIOS from NeoSD's screen? Unless you mean AES/MVS and region. Would having a flash cartridge for Naomi guarantee you get the same ability? I'm not sure how Naomi handles regions, but I always thought the releases were region specific, and didn't contain all regions, or at least JP/EN, which would boot according to the BIOS language.
If board requires less power, you should be able to run with the capcom I/O
Naomi is the only board requiring aux power to run a NetDIMM. Naomi 2, Chihiro and Triforce don't. I don't have a Naomi power supply, so I'm running power from a PC supply, via supergun and Capcom I/O. Everything works fine. Besides, if you're planning on playing Naomi games, there is no reason why you would choose Naomi over Naomi 2.
Possible access to game soundtracks via jukebox mode
This would only work for compressed audio, which in many cases with Naomi games would be ADX, but not all games work like that. Some use sequenced instruments. Who is listening to music on their arcade machine, anyway?
This post wasn't meant to counter everything you said, by the way. It was just easier to respond in this fashion. Like I said, I wouldn't mind having a Naomi flash cartridge as an extra unit, if the price was right.