OK, it's obviously cheaper to build, therefore allowing a contractor to offer better value for money and could mean the difference to keeping the firm going or shutting the gates especially in a flooded market.
The required training and experience required to erect it is less than tube meaning less skilled labour required and cheaper over-heads, again meaning more profit for a contractor.
Design input is still required for a lot more structures than many realise but the manufacturers guide lined do give you a bit more scope for the more basic jobs.
Easier to handle, stack and transport even storage is simpler.
There will be a few more but that's the basics.