I know very little about surfing, can I ask why it is so dangerous?

The biggest danger is being shredded.

Why is such a wave so big? Because the coast is extremely shallow suddenly. Normally 1m-50cm, but when a big wave comes, all the water in front of the wave is sucked into it back, which makes it about 10-20cm deep. And it is sucked back really fast, because it is not deep. So if you miss such a wave and fall down, you end up there in the impact zone, which is also the shredding zone. There are either rocks or coral reefs, both extremely unhealthy when being shredded along, even if you still have your board. Normally not. And then you are sucked back into the next wave impact zone with high speed, which is un-nicer, because then you are not just shredded along, but also hit big from above into the ground. Where you usually break some arm or leg, or just hit your head into the rock and then drown. The few people who survive this do have professional help by the jet skiers, who try to catch you before the next impact. Your only chance is to get your board from the leach as soon as you get up, and paddle as fast as possible to the side, across the stream to survive the next impact.

It's not interesting at all, pure danger. Like running across a highway without looking.