Appears to be a useful app, with a plaetora of features, but gathers your personal data, including voice, just to sell it to the highest bidder, all under the umbrella of an ads platform (which is also a very sketchy business).
I'm afraid you are deluded if you think all your data is safe with Google.
Ads make money, because the valuable data can be sold.
Google collects data about you and by doing so, is able to target you with products that are suitable to you.
Other companies will pay top dollar for that kind of data. From Google trends, to purchasing habits, sentiments around world events, elections, sports events and betting...
It's all useful to other companies, not Google. Google just wants to collect it all and create a product out of you that can be marketed to people who want to sell you stuff.