Depends what pitch goes on the roof of the rectangular shed and weather proofing is easy enough.
I do it on houses, commercial properties and outbuildings.
Don't get me wrong, I like the look of these pods but if I'm building a shed to actually use myself I'd build it with more plumb walls (they only have the two ends plumb and possibly an internal partition) that I can put shelves on with ease.
Definetly, square walls are more useful.
I was just thinking of the old bomb shelters, they used a similar system for its added strength.
The continuous curve acts like an arch and keystone. The forces are directed to the foundations smoothly. This plus the curved roof would make snow less likely to gather and therefore build up.
As for waterproofing... A slanted flat roof is simpler and cheaper.
But the slant for snow to slide off would have to be up above 40° other advantages would come from the better volume to surface ratio. This has advantages when it comes to heating and insulation costs. (not counting installation costs)
All this being said, these are all mostly academic, as the uk doesn't see enough snow to collapse the average garden shed, and most people are not looking to save a few pence on heating at the cost of shelves and more usable space.
I think these are more a form over function idea, building on the old anderson bomb shelters and Arctic style tents. Which were designed to be quick and cheap to put up.