Self-burned discs is just added protection, ideally you should also have the files themselves stored both locally and on some form of external drive as well.

And technically, BD-R HTL discs are chemically similar to M-DISC DVDs in that they use an inorganic composite to store data where BD-R LTH discs are dye-based like CD-Rs and normal DVD-/+Rs, so they should be more robust because of that, not to mention M-DISC DVDs themselves use glassy carbon to store data.

Too bad there was never a CD-R equivalent to M-DISC DVDs because those would've been handy for burning WAV files or even FLAC files as an audio CD for long-term archival.