Do you know how many YEARS we waited for a flashcard that could hold all games at once? A few months won't kill you. You could also subscribe to the Flash Masta blog and purchase one of Flavors excellent cards when they become available again.
Just recently, I dug up my Flashmasta cartridge, and as it turns out, it's not that excellent in 2017. It was a major pain to get it to work on x64 Win 10, and even when the software could finally detect it, it detected it as a legit game cartridge, and the write option was disables. There's really nothing easier than putting images on an SD card. Full disclosure, though. I have the earlier version of the cartridge, without the switch allowing you to store two games at once.
Still, a choice between having one or two images written to a cartridge at any given time, and having all of them on an SD card is simple. Get the SD card one. I might just get it as well, since my current unit refuses to cooperate.