Fair enough, but being better than nothing doesn’t mean it’s optimal.
Exactly. In effect, this prevents the creation of a habit (or at least lowering the resistance to doing the task regularly), and keeps us dependent on Beeminder to do what we want to do. If Beeminder’s goal is to become obsolete, then it should promote the internalization of the extrinsic motivation it provides.
Of course, this depends on the type of activity you’re beeminding; some will be always unpleasant and a chore, others you can get into it once you started, as @drmaciver brilliantly explains. The fact that Beeminder is agnostic about this distinction means that it should support the worst case, i.e. the chore-like tasks.
I think that the obvious tool to prevent surfing the buffer is auto-retroratcheting. I really miss it, although I understand the economic reasoning behind turning it into a premium feature. That said, I believe the philosophy of Beeminder is to work well for the basic case out of the box, and chore-like goals are common enough to justify having that feature available for everyone, imo. Maybe only keep the customization of the buffer length as a premium feature?