The pop-up blocker that comes with Opera mobile doesn't work.
For example, a website I use to watch TV series and movies - primewire.li has pop-up ads that some other Android browsers can stop, but not Opera.
Brave works, Firefox works, Kiwi with uBlock Origin works, GxDroid works.
But Opera doesn't work.
If you don't believe me, go and try to watch a movie or some episode with Opera mobile and tell me that I'm wrong, because I'm sure you will be bombarded with pop-up ups instead.