It's a weird halfway house.

I had a cheap Casio fx calculator. It got me all the way through my exams in school and university. I had Mathematica at home.

While I can see that being very good on a TI-84 would help you complete exams faster and get better marks, is that a skill that we want students to learn? Being good on a fancy calculator is essentially useless in real life. In real life people use computers not fancy calculators.

IMO it's better to either allow only basic calculators, or to allow real mathematics software.