If the (usually overpriced) Galaxy J series had any fans, they will definitely love the Galaxy A lineup because Samsung has just confirmed that "Galaxy J is now Galaxy A" in a YouTube video. The existing Samsung Galaxy A10, A20, A30, A50 and A70 will be joined by a few new models on April 10.
https://www.notebookcheck.net/Samsung-confirms-Galaxy-J-is-now-Galaxy-A.415991.0.html
Arguably "J" just screams low end, "A" leaves more room for interpretation at least.
Yes, the family's name as a whole sounds better. Not to mention that probably the upcoming A90 will drive many customers with low budgets towards the cheapo low-end devices in the Galaxy A lineup.