Yes, you can use Node Buffers (which are not that bad), or JS native Typed Arrays (which are also not that bad but a little clumsy). Yes, in embedded systems, that might be really important so it can get clumsy.

It's not the best tool for the job. It's also not the worst tool for the job, and it's an extremely popular language. If it brings more people into the hardware space (which is its expressed goal), it will be a success.