Even if you go the cheaper route, replacing the polycarb with lighter, cheaper and more resilient HDPE, it still is a huge investment.
Covering a full HW arena roof in 5mm HDPE is at least £1200 (I know from first hand experience), and that's only the HDPE sheet. With ali trussing and connections, in a creative configuration, add another £2500.

Transport is more a question of volume than weight in this scenario, but that has a pricetag too.
Combine that with the time to raise and break down, what is at least 10 manhours extra per venue