If everything were to go according to plan, it would be harmless, yes. The problem is that data becomes a liability.
The same way having a few sparklers in your closet safe enough, having a few websites of your users is safe. But when you have a huge cache of personal data from large numbers of users, it becomes attractive to foreign governments, foreign gangs, feature creep from questionable law enforcement practices under a corporate surveillance state, unethical domestic lawyers, script kiddies, and so on. It's like having a whole fireworks store in your closet... It just keeps getting harder and harder to store safely the more information you collect!
And you're not totally wrong- at least they're doing the right thing and making this opt-in. However, this collection appears to be one done by a bunch of GPU nerds, which raises warnings that it won't be protected as well as, say, google doc data.
The same way having a few sparklers in your closet safe enough, having a few websites of your users is safe. But when you have a huge cache of personal data from large numbers of users, it becomes attractive to foreign governments, foreign gangs, feature creep from questionable law enforcement practices under a corporate surveillance state, unethical domestic lawyers, script kiddies, and so on. It's like having a whole fireworks store in your closet... It just keeps getting harder and harder to store safely the more information you collect!
And you're not totally wrong- at least they're doing the right thing and making this opt-in. However, this collection appears to be one done by a bunch of GPU nerds, which raises warnings that it won't be protected as well as, say, google doc data.