Sütterlin is very ancient. I knew someone how used it for handwriting, but there are only a few people that really learned to read and write it.

In Algebraic Number Theory it's quite common to use some kind of Fraktur-Alphabet for Symbols (Rings, Ideals, Groups,...). It's natural there to use some kind of Sütterlin for hand-writing and exercises. But I think to become really fluent, you have to dive very deep into Algebra... There are some letters you'll use a lot like p(rime), M(odule), G(roup), R(ing), A(lternating Group), S(ymmetric Group). I don't think I've read/written all available letters yet...