Certainly tends to be popular with kids in the UK as a quick and easy dish: Put them under the grill (broiler), heat some backed beans, butter some bread, fruit for desert, and there's a reasonably nutritious fast food lunch once a week that can be prepared in a hurry.

On numbers:

A quick search [1] suggests 1.5 million fish fingers are eaten per day in the UK (18 per second).

A US search was less easy, but at 25,000 tons per year, and 26 grams per stick, that'd be the equivalent 2.6 million fish sticks consumed (purchased, I suppose) per day in the USA, which on a per-capita basis is interestingly much less.

[1] https://www.intrafish.com/marketplace/youll-never-guess-how-...