[alrs]

Who cares about scans? Who cares if a scan comes in 4 or 6?

[account42]

I imagine it stops some non-targeted attempts that simply probe the entire v4 range, which is not feasible with v6. But yeah, not really buying you much, especially if there is any publicly listed service on that IP.

[kbolino]

Forget IPv6, just moving SSH off of port 22 stops the vast majority of drive-by attacks against sshd on the open Internet.