Definitely a hit for me, giving Brown 11 terrible numbers right away (9 fans plus 62), after which Yellow can go after the loose blot. Hitting also robs Brown of many point-making numbers.
Primes are pretty, but they don't give Yellow license to play passively when she is spareless and down 15 pips. If she doesn't hit, Brown's back checker will continually be a threat to run out. The 31 roll offers Yellow a way to push that edge blot back (or better) -- she should view it as an opportunity.