All that they have done is to lay out the things that you should take into account when you design temporary roofs if you decide to or have to follow the current codes of practice (which have been around now since 1995 in pretty much the same format). The real load cases are a lot more complicated than even they have suggested because design wind speeds from different directions are different. If you use the Euro or British wind codes for roofs, you only get tabulated information on wind zones pressure coefficients for orthogonal wind directions but you should consider winds from more than just 4 directions, giving different load intensities and different zones. Introduce variable internal pressures to account for the wind getting through all sorts of holes in side sheeting from different directions and your head will really start hurting.
If you had to design every temporary roof to comply with EN1991-1-4, the industry would grind to a halt because there is no computer program out there that can do it properly and the cost of the number of hours necessary to prove the simplest roof is way over the cost of the hire.
It is another example of a representative body taking a complicated situation and multiplying the complication by a large factor instead of simplifying it by the use of experience. The academics behind Eurocodes are the original source of this problem because they don't live in the real world where things have to get done. Instead, I think that they treat the development of codes as an 'interesting discussion'.
It may have been done quietly but on their web site it says currently being updated so perhaps they have not finished it yet?