Currently, the maximum daily coin goal is 400 coins. It would be great if users could set their own custom goal. People use LingQ differently and earn coins at different rates depending on their activities - it therefore makes sense to let them choose a daily target that matches their own study style and objectives. I know that I can set my own personal (mental) goal beyond 400 coins, but there is something motivating about having the in-app target and seeing the streak/fire icon associated with achieving it. The fact that LingQ already includes this goal-setting and streak functionality suggests that these visual milestones have value for many learners. Allowing custom goals would therefore make the system more flexible without changing the underlying mechanic.
I agree with this. Having a fixed 400 coin limit feels pretty arbitrary. Some days I study way more than that, and other days I might only have time for a lighter session. Letting users set their own daily coin goal would make the system feel more personalized and motivating.