If you have never heard of M-pesa till number, I will briefly tell you what it is. Now, don't confuse it with the Paybill number because they are different. A till number, in my opinion, is an easier way of paying because it only required the till number for payment.
A paybill number, on the other hand, has a business number, and an account number, and can be confusing to a person not conversant with it. It will also waste a lot of time, especially if most of your clients are paying through it. Imagine that you have a supermarket with 50 customers in the queue, using a till number would be faster than using a paybill number.