In my case hardware acceleration may randomly cause system crash like following while browsing a site. This bug related to Linux AMD graphic driver. This is Chromium bug since it the same for Opera and Vivaldi. I'm using both browsers every day and I intentionally disable hardware acceleration in Opera and enable in Vivaldi as longtime experiment.
As the result, the "hardware acceleration" option in Opera 71+ for me is now a switch between unusable UI and potential system crash. Keeping Opera 70 installed.