You'd be skipping the numbers in between 0 to 10 when you're counting by 10's.
So it would be 0, 10, 20, 30 compared to counting by 1's,
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14.... it appears longer, you would have to say each individual number in between the tens, so it would take longer.