They are advertising, but the point isn't that all advertising is inherently bad. The point is that we've normalized a really unhealthy amount of daily exposure to it and it turns out we are way more susceptible to it than we like to admit.
(That's what they actually do).
If your examples did it - it'd be flashy, colourful, gauche, impolite, nonsense. Scammer grade low class bullshit.
No-one likes having evangelists knock at their door, because they're annoying and interruptive.
I mean, maybe in Ulm? [0] But I can rarely see a church tower over trees and other buildings within a fraction of a mile away.
Generally it's a pretty sight though, not like billboards at all...
No...instead, I can walk down almost any street, and find a sign out by the road imploring me to come find Jesus, or some other pap - and I can usually pass by 3-4 within less than a mile of each one (we have more than one street here where there seems to be a church of one form or another every few hundred feet for a couple of miles - not even joking).
Welcome to America, I guess, where churches are big business (that's putting it kindly).