IMHO mid air collisions are the worry.

The closer to VNE you fly the simpler the lookout and
collision avoidance issue (with respect to other gliders)
becomes.

Close to the ground there is less chance there is of
hitting a glider in the blind spot below you.

There are generally more gliders around an airfield
then anywhere else.

Ergo, if you want safe finishes, (including avoiding
close outlandings) you want to get gliders back low
and fast and look at the issue as one of flow control
i.e. does everyone know where to go and what to do
after the finish pull up. This is, in effect, what
has been informally and safely sorted out by pilots
and comp directors for decades.

A close remote high finish potentially leaves a number
of gliders milling around at or below normal circuit
height getting in each others way and increases the
collision risk.

John Galloway