As posters have said, it is hard to know whether they are worth it at this point because so much depends on factors specific to the applicant and the schools considered.
On balance, and on average, I’d say it is worth taking and submitting subject test scores if achieving 750+ would require relatively little effort. If it would be tough to achieve those, then my gut tells me an applicant is better off concentrating on other aspects of her admissions profile.
Best of luck, OP, whatever you decide to do.