It is basically very slow RAM (or very fast flash), which is bit-adressable. So you are not, like with flash, erasing 64 KB sized pages, but you are doing things to individual bits and bytes.
It’s also faster than flash (but slower than DRAM), about 10x faster than old Commodore 64 memory.
And it’s persistent, so if you power off your machine, contents are not gone.
And it is very dense, denser even than the memory you currently use, because no transistors, so less space necessary per bit.
This is going to change a lot of things, but not right now. We need to rethink our approach to persistence.