If typing digits occupies a significant portion of your code creation time, something else is very wrong. It is almost always a bad idea to have many numeric literals in code; instead they should be single-declaration constants, user-settable options, injected or imported data, etc. Typing rows of numbers really should be an issue for data entry clerks only, and not for programmers.
That said, if you do have something that requires columns of digits to be input, the numpad might save time, but one way or the other I don't think it merits long reflection - the difference will simply be too small to matter much.