The rubber hits the road with this issue WRT the duration of the duty day and when and how much relief the company gets. Going 9-10 bock hours instead of 8 might be safer if its all done on a front side of the clock, 11-12 hour day, CONUS only flying, with no "legal to start legal to finish" relief whatsoever.

But the second you throw in a hour or two duty day relief for "beyond control of the company" and/or allow EVEN MORE block hours, not to mention fantasy based circadian reset windows and/or add in 3 hour 2 pilot ETOPS to these new higher block hour days and it quickly becomes a net safety decrease in some areas to help "pay for" net safety increases in other areas.