I'm afraid I'm not entirely sure what the original intention was there.
Is technorama still around? Could we ask her/him?
If not my guess is that the intention was to read a point from OctetString
representation as described in section 2.3.4 in [1]. However, this would
probably also require an additional parameter that indicates the point
compression form. It would be a valuable addition, as well as having a
method for the inverse operation, ECPoint#to_octet_string. If we can't
reach technorama I will implement these two options. Or did the OP have
something else in mind?