Please understand tho that with MAME the Software Lists are the recommended way for running things.
A lot of Software, especially for the consoles, WILL NOT WORK PROPERLY if you use the loose ROM loading, as it relies on the Software Lists to specify the extra hardware in the cartridges (especially custom mappers, NVRAM etc. things that we don't want to have to add a ton of ugly hack code to detect from the ROM data alone) This isn't so much a problem for tape / disk based media, but for cartridges it is important.
Non-softlist use also encourages poor dumping practices (single ROM file for multiple chips etc.) with no incentive for people to do things properly.
Furthermore, loose ROMs encourage people to keep bad dumps around, with no incentive to replace them as the software still runs them and won't report any issue with the dump (the emulation problems as a result of these bad dumps may not be obvious, this has been a problem in the console scene for years and would have been for arcade emulation had we not gone with our own database from day 1. Even when redumps have been around for years in the console scene people keep using the old bad dumps they already have, sometimes the good dumps actually fall out of circulation as a result because the emulators aren't making people aware they should replace their bad ones)
We've been heavily dissuading people from using the loose ROM loading for these reasons (to the point where I'd really like to see it locked out by default for systems with mature lists unless some 'development mode' switch is flipped in the ini file)
Softlists are a "MAME only phenomenon" because part of what MAME does is recognize where the existing scene is failing and attempts to do something about it by pushing people in the right direction to ensure a better future for everybody, even if it seems less convenient in the short term.
If your 'BletchMAME' is encouraging users to ignore Softlists, that is a problem, and is damaging to the core project and the user experience. If you champion a path of least resistance, people will take it, this is not beneficial in this situation.