>> why do the “devout” participate in what I would call “symbolic fasting”? <<
Wouldn’t it make sense to ask the person who’s doing it? As someone who has done it, I can tell you that removing a little something from your daily life makes you remember God every time you reach for that little something. It’s not meant to be a sacrifice; Christ’s sacrifice is sufficient and eternal. It’s just meant to remind you to appreciate his sacrifice, and to decide to follow him.
I am curious, what is the model for this form of “reminder” service? What Scripture can be cited as warrant for this activity?