Despite being mostly a subset of UML, SysML is a more cohesive and useful design and modeling tool. Unlike UML, I've actually used SysML on real embedded systems projects and like it. It lends itself well to model refinement, wheras UML encourages Big Design Up Front.

I'm not sold on the idea of capturing an entire design within SysML, but using it instead as a diagram format with defined semantics for situations where group discussion or communication with third-parties calls for some graphical aids. I think as long as you're not trying to make executable models, do code-generation, or replace a formal specification tool like TLA+, there is real value in it. The documentation and training ecosystem around it is pretty decent, as well. The SysML books I've read have all been way more pragmatic and grounded in actual engineering practice of building systems from many components sourced elsewhere, for which design capture is necessarily incomplete.