No, the idea is that bees are useful because pollinators, and honey.
However, wasps may not be the friendliest creatures around, but they are certainly useful too - like cleaning up corpses, leftovers, and last but not least they eat insects that we think of as plagues
As they are insect hunters, yes their absence would fuck up our already damaged ecosystem. I would guess it would lead to a different insect getting out of control and causing tons of problems - like a non native leaf miner who then proceeds to multiply like crazy and obliterate all leaves off trees kind of deal.
Check out the book (or audiobook) Endless Forms by Seirian Sumner! It's a fascinating exploration of the different kinds of wasps and their role in their environments. For example, some figs can only be polite (typo: pollinated) but a certain species of wasp and some wasps use antibacterial compounds to coat their nests.
That depends. How indepth is it? Are there pictures? I ask because I generally don't like bugs. They give me the heebie-jeeies. Especially big insects or swarms of insects. Which is a shame because they are fascinating creatures regardless.
I honestly have no idea if there are pictures because I listened to it, but it does have a pretty accessible breakdown of their anatomy, physiology, and evolutionary biology. Like David Attenborough, but with more words instead of video, and more of the author's story.