It has been a while, but I'm pretty sure the bladed weapons are needed because the shields specifically block objects with high kinetic energy. I also recall one of the houses on arakis getting bombed, but only after they were able to turn off the protective barrier. I might be mixing up Sci fi books, though.
You’re not - it’s pretty explicitly the point. The technological arms race has gotten so advanced that everyone has devolved into fighting with knives.
You are correct. But the movies did indeed make a poor introduction to the shield technology. I think it was just a short mention when Gurney is training Paul and is easily missed. They even have to train for a specific fencing style that involves slow movements as a fast swung blade can still be stopped by the shield. And I don't remember them talking about the interaction between lasers and shields at all, which creates a huge explosion.
My bigger issue with the movies was the typical hollywood charge. No tactics or strategy involved at all. Just screaming and running.
The shield-based fighting style was also a small note that was missed in the duel between Paul and Jamis in the movie. Paul was missing what they thought were clear cuts and as a result they believed he was cruelly toying with Jamis, but it was because he was slowing his blade at the very last moment due to shield training.
Also a slightly weird moment for me as a book fan was when the thopter Duncan escaped in clearly showed that it had shields with a rock crashing off of it, but then he was being chased by lasguns immediately after.
The movie had its problems and I've never read the books but even I know the answer is because the shields don't stop slow moving objects otherwise you wouldn't be able to pick up a cup. It's even explained in the film, admittedly very briefly.
But then again that's also how personal shields work in Stargate