Sort of. Yes, it was partly done to help prevent confusion, but the primary reason the localization team for the NA client decided to use roman numerals for spells is for the sake of consistency and clarity. In the JP client the spells still have the -ra, -ga, -aga naming convention, but so do other items such as materia (Materia, Materira, Materida, Materiga, etc.). The problem is there was no consistency between everything that used that naming convention (the -ga spells corresponded to a different rank than the -ga materia, for example) which could easily lead to confusion, so they simply gave everything a roman numeral instead.
I do miss my -ga spells, but given how it was before I can understand why they changed it. I'm also glad they changed everything so it's consistent across the board, instead of only changing bits and pieces.