From another site:
There is speculation in the PlayStation homebrew community that the change was a way for Sony to sneak in code that will hamper modders. An online check-in is a common tactic against modded hardware, as it prevents illegally downloaded games from being played on the console unless it connects to the internet, which then begins the process of downloading and installing the latest firmware.
Inconveniencing everyone because of a sale you never had. Brilliant.
No. Previously, if you bought a game digitally, you could play it indefinitely offline. You’re probably thinking of free PS+ games, which is different.