Anyone heard of these/used them?

Zefal skewer set

They seem a really clever idea as the quick release only works whenever the bike is upside down(only prob I see is how you adjust your saddle height upside down).

These would save me time when locking my bike up(I commute to work every day) as I have my kryptonite new york lock and then use a kryptoflex cable round the wheels and thread through the new york lock.

Doing this a few times per day(locking and unlocking) can be a pain in the a**, so I wondered if these would be any better.

My experience of exposed cam QR skewers is that many of them have problems holding your wheels on as well as an enclosed cam style. If the skewer uses a weight that acts as a latch based on the orientation then tapping top or bottom of the skewer with a hammer while opening may well allow them to be opened while the bike is upright.

The best way to not have your bike stolen is to make it less attractive than those around it by either never washing it, locking it near the most expensive shiny looking bike you can find, or putting a disproportionate number of locks on it so taking it looks like too much effort.