Yes they would. But you have to be able to use it to solve real problems.
Alternatively, you could be a dev who supports a science team.
...On the other hand, if you're already a dev and want to become an ML Dev, knowing how to do science deployments, work with big data, and familiarity with APIs like TF would be more valuable than knowing how to do proofs.
Similarly I suppose most ML work is done with some solid basics but advanced math textbooks aren't really needed, and people actually working at the theoretical advanced math level are rare and in a handful of academic positions or corporate research labs requiring high credentials or other specific qualifications.
Thanks for your input.