High capacity SD have a miserably failure rate with regular use. In PI's and dashcams many only get a couple of years before they start having errors. USB thumb drives do better but they have heat problems. neither are great for backups unless you just do a lot of write once and store

Today? Of course. But until recently that wasn't the case. Longevity though.

We got prediction of sector failure rates on HDDs and magnetic tapes down to a science. Makes archiving really easy as you know with statistical significance how often to test, copy and move data, to preserve it virtually forever (as long as there is someone maintaining the archive).

Solid state memory can be extraordinarily dense, but the denser it gets, the more it's prone to corruption and failure. Worse still, when solid state fails, the whole storage unit becomes obsolete, and data gets nightmarishly hard to extract, maybe even gone forever. Only with very rare and specialized workshops that have the equipment to do it. On the other hand, I've seen technicians recover data from tapes that were literally in a fire, right there on the field with bog standard equipment.

When you factor in that the average cost of a terabyte of magnetic storage is less than half of the average cost of a terabyte of solid state, then a few cubic centimeters of space per unit become practically irrelevant. Corporate settings actually prefer more smaller storage units than larger, as they cause less trouble when they fail. Redundancy is a numbers game.