Such is the case with popular third-party keyboard app SwiftKey, in which according to emails Google has been sending out to Gmail users, it looks like the app could see a reduction in quality and functionality due to some policy changes that Google has made that are supposed to help protect the user’s data.
It seems that Google has given SwiftKey a deadline, which is set for the 15th of July, to comply with these new policies, otherwise they will be losing access to data in a user’s Google account. Note that this only affects the app if it tries to access data on Google accounts, which means that for other apps and purposes, it should still be fine.
However, one of the features of the app is the accuracy of its suggestions, where it can learn over time the way you type, which is also based on being able to scan your messages to better understand your writing style.