Yes, I've no problem with someone using a dice app. Of the people I've known that cheated at the table, they all "rolled" their dice physically.
While I voted "no", a more correct answer is "conditional based upon game system and player disability"...Do you allow players to use electronic / smart phone / mobile app die rollers at your gaming table, and please comment if so, why, and if not, why not.
Thanks!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.