Temporary becomes permanent again

It is pleasing but unsurprising that the 'temporary' Skyroom built on top of the Architecture Foundation's home near London Bridge is to become permanent, as BD reports today. From the Eiffel Tower onwards, there is a long tradition of so-called temporary structures acquiring a permanent life. In London of course the most prominent example is the London Eye.
The Skyroom is far more modest, although it was designed by David Kohn, who subsequently went on to design the far higher profile rooftop pod 'Room for London'. Owner Roger Zogolovitch is hoping that he will get planning permission to turn the Skyroom into a flat.
It all seems eminently sensible, and Zogolovitch made no secret about wanting this to be permanent from the outset. it fits with the British sensibility which hates to see anything new, and then hates to see anything disappear. I just have one little concern - if so many temporary uses become permanent, will councils become wary of allowing 'pop up' interventions to go ahead?