Theory: Challenges are temporary because they are tools to collect gameplay data

"Chicklet453681;c-18015204" wrote:
That's my theory. Timed events in an offline game doesn't make any sense to me.

The value in timed events in singleplayer/offline games is in keeping people engaged and playing so they'll be more likely to buy DLC or other value-add-type content. Every time someone opens up their game, that home screen is aggressively selling them something. More "impressions" on ads means more "conversions", and that's what the home screen is, the ultimate targeted ad.