Used to be common in archery. Face walking is what it was referred to around here, and potentially many more than two anchor points were available.
Also walking the string. Same basic thing, done a bit differently, by moving your fingers up or down the string in predetermined amounts (maybe, five string wraps of the serving). This was typically used by those using the point on or gapping aiming methods.
Works, very well in fact once you get to doing it right. Well enough that it was considered an issue in league and contest shooting.
It is just another way of aiming. Every time you add another layer of technology it helps make things "better". For most, if you add a sight pin, you can shoot more consistently. Add a rear sight to that, a release, a stabilizer etc etc and it just gets better, quicker. That's why there are classes in competition.
ChuckC