At first, there is one thing you might hear or not: If a product is free, we – the customers are part of product.
Looking at this screenshot, you would see
For 3rd party keyboards on iOS, there is an option to allow them to connect to an internet server for advance features such as “improve prediction” :). So here is my guessing: both MS and Google are now on the way to collect user typing characters or else I am aware of. What are their big picture behind? Let’s think in another moment.