It might be gambling for some, but prediction markets are impressively accurate, in a way that I think merits OPs comment that the information they produce can improve lives. (Other lives will surely be destroyed by gambling...)
There's quite a bit of interesting research done on the accuracy, here's a great resource:
What value does an accurate prediction market bring? I.e. how can this information be used to improve lives (other than the person winning the bet)? I.e. even if it is sorta accurate, is this valuable to anyone?
Great for the person who has insider knowledge, probably not so great for Google.
I wouldn't be surprized if some companies start cracking down on their employees making bank off unannounced company actions.
There's quite a bit of interesting research done on the accuracy, here's a great resource:
https://calibration.city/introduction