Streak Freeze always equipped
Advice to others on how Streak Freeze works. I thought it was a bug.
Once Streak Freeze is equipped, it remains active permanently until it's used (by you reaching midnight without achieving your daily XP goal).
So it does not count only for the day that you purchase it (similar to a Weekend Amulet). You can activate it on January 1st, and it will remain equipped until you skip a day 6 months later, at which point it will prevent your streak from being lost. Only then will you see the option to purchase a new one.
So it is a good idea to always have a Streak Freeze active, to buy one in advance, not just on the day you need it.