RFC 6164, Using 127-Bit IPv6 Prefixes on Inter-Router Links explains that /127 networks are good for point-to-point links:
On inter-router point-to-point links, it is useful, for security and
other reasons, to use 127-bit IPv6 prefixes. Such a practice parallels
the use of 31-bit prefixes in IPv4. This document specifies the
motivation for, and ...