From a safety point of view.
There was a regatta earlier this year where a skipper on a boat going downwind appraoching a gate
was struck in the head by the end of a spinnaker pole of a boat that had just gone through the gate
and going upwind (both boats were going at speed). The person who was struck was in the wrong. He didn't see the upwind boat because he was concertrating on the tactical battle.
While this is no excuse, the danger to him would have been much less if the other boat had the pole retracted.

He was an extremely lucky person to come out of it with bruising , abrasion and a very bad headache.
If the pole had been a direct end on blow and not glanced off his forehead or been a couple inches lower
it could have been much worse.

I think it would be great if someone could develop a retractable pole. Apart from the possible performance
advantageous it could also ensure this type of thing does not happen again, the outcome could have been
disasterous.