Playing on pad can hinder your performance and eventually you'll notice it. (IE when you get a throw break and both go for an immediate 2k but you lose out simply cause you had to slide your thumb but they only had to press a button.)
However it all comes to preference. There are some things that are just not possible on pad. For instance I can't FRC I-No's Throw into a P-Dive on pad because the FRC negative edges the 236 into a S-Dive instead.
5K HCL AIRDASH is 1 step away from impossible on pad.
However despite being able to play I-No on stick, 5K HCL and all, I still prefer pad and can hit my FRC's about 90% of the time.