It's an interesting topic. And one that many people can learn from. I think the biggest problem with electricity is that you can have something working fine for years. Then oneday from a build up of carbon or heat etc it can just go bad. I've seen some pretty crazy things as an electrician. Everything from a nail in someone's mains (to steal electricity) to a completely melted fan switch. And I don't even work on houses for a job
There is a very high chance that you will never have a problem with plugging power boards into powerboards. But there is definitely a chance it could go bad as well. I've had a powerboard catch on fire on a fish tank when I was a teenager. Luckily I was home and smelt the smoke. The PVC burning stank... It was just the result if a faulty powerboard. It's impossible to get around using powerboards. I still use them. But keep an eye on them. I don't trust them at all!