Most of the time, when I hold the backspace key down, the cursor disappears, and I can’t tell how much is being deleted until I let up on the key.
Note: This may be in part due to my computer. I’m running Windows Vista, and there are times where my computer lags in recording changes to text as I type merely due to a poor ratio of memory available to memory used. However, once triggered, this seems to continue until I let up on the key, which isn’t normal for my computer, which will usually only lag by a dozen or so characters.