This is a bit short-sighted. Yes, it is kinda tricky to get right, and a number of programming languages are quite behind on good SIMD support (though many are catching up).

SIMD is not limited to mathy linear algebra things anymore. Did you know that lookup tables can be accelerated with AVX2? A lot of branchy code can be vectorized nowadays using scatter/gather/shuffle/blend/etc. instructions. The benefits vary, but can be significant. I think a view of SIMD as just being a faster/wider ALU is out of date.