Personally, I am infallible and have no need to remove a single character that I have ever written. However, I am assuming the rest of your users may misspell a name on occasion, or perhaps misplace a '.' in an email address on occasion. For those unfortunate individuals that fall victim to their own imperfection, the ability to delete said error via the backspace key may be very handy.
This sort of cutting edge functionality is not something I usually share without a consultative fee, but I am feeling extra generous today. So this one is for free.