

Yeah, I like to have important data (such as family photos and videos) backed up on two different formats and M-disc BDs provide an acceptable option. There are various blog posts testing them online versus regular discs and they handle a lot more wear and tear (not that mine get subjected to that!), so I’m pretty confident that mine will outlast me.
Entertainment content I’m willing to risk on regular recordable discs/HDD backups if it’s important enough to put in the effort (I usually buy the physical disc anyway, so I have the pressed CD, DVD or BD to start with).
Haven’t seen a minidisc in ages! I remember some of the cheap IT hardware used to come with those for drivers in the late 2000s.

Ah, my mistake, I’m getting mixed up between minidiscs and the 8cm mini CDs.
You can get multi-layer M-disc BD-Rs, though, up to the triple layer 100GB BDXL (although you need one of the BDXL burners to write those; the 50GB BD-R DLs can be written by most burners). They cost a pretty penny, though!
The biggest problem now is the disappearance of Bluray burners/writers. Here in Aus there are no internal drives available on the market any more. I’ve had to stock up with a few second-hand spares before they get too pricey.