This is in general for LED text signs. The “inventors” (more like engineers because they just combined multiplexing with superbright LEDs) OP mentioned probably didn’t specify a purpose, they just wanted a more reliable alternative to mechanical or manual signage but yes, most are for ads.
I mean, I don’t think an advert needs to be illuminated at all, frankly
This is in general for LED text signs. The “inventors” (more like engineers because they just combined multiplexing with superbright LEDs) OP mentioned probably didn’t specify a purpose, they just wanted a more reliable alternative to mechanical or manual signage but yes, most are for ads.
They also don’t need to be visible, or exist at all for that matter. I despise ads.