all assumptions are valid & reasonable
however I never treat a flashcart like a memory card (SD/CF/any other form of mmc)
because MMC tend have lifetime warranty
treat or think a flashcart like a generic card reader
it meant to be expendable because it is expendable things, it doesn't really matter how expensive this card reader if it's broken then it is broken.
flashcart for NDS Games (either compatible or not with 3ds) are pretty much obsolete, almost no new games (or at least decent games has been released)
and it quite endless to argue which one is better
Pros & cons are obvious, look at the price, sure it's not that much if you think about it, how about adding example with another digit add to it? $3990 vs $800?
Cheaper one often get abandoned but if it's not broken it will work for older games, while the expensive one get support like almost fast enough to cover before user are complaining (only for supercard tough)
but still doesn't matter which one, anything made by human will be broken someday.
TBH it's all about kernel inside it, and at this point, only 2 developers active to support roms for nds (wood & SC team, well if you consider Retro then 3)
I own SC SD long time ago, they said they will never release or revised their product, but after a while.. MiniSD was released, and probably at this point they already stop supporting those types.
I'm not saying don't buy it.
in the end it's for you, it's your money
if you think better value is better for you then get the cheapest R4 with wood support (ace3ds also included).
if you think better support is better for you then get DSTwo.