Whether or not the provider makes the customer pay with a credit card has no impact on if the provider requires templated SMS messages.
Could easily be one person writing the message. Another who demanded partial edits in a Jira ticket. But then the data types didn't match up with what the writer requested and then the dev didn't want to deal with it and just shipped it.
Or it could be that the message is made with a bunch of disjointed and constructed if statements and only the final output is piped to the customer. I have seen some very terrible log messages like that as nobody is looking at the entire message, just the little bit in the conditional they are editing at that point.
As an anecdote, I once worked on code that generated these very detailed error messages about why something went wrong. I discovered most never made it to the customer as someone later down the line reassigned a variable rather than +=. Piles of support tickets could have been avoided.
These days though, like most scams the 419 scams have been taken over by organized crime and worse. The average Nigerian scammer nowadays is probably doing it because Boko Haram will kill their family if they don't.
Just doesn't make much sense for people whose time is valued in cents per hour and whose theoretical earnings are in the thousands to optimise for screening out non-gullible people, plus the 99.9% of gullible people that have some sort of spam filter in the loop. But hey, if someone's shared that Microsoft Research paper with the scammers and they've come to believe that using formats that almost invariably bump into spam filters is actually a shrewd move on their part, who am I to discourage them?!
I don't know about Boko Haram involvement, but I assume the organized crime guys have some sort of MLM-style operation scamming Nigerians into paying for the get-rich-quick opportunity.
"Incompetency" is an interesting word.
The old maxim about incompetence versus malice suggests a binary choice.
I prefer the more nuanced take that there is a spectrum of positions between the two, and other dimensions that describe a cluster of intents, both conscious and unconscious.
Take the UK Post Office scandal where we see incompetence layered on top of malice, layered on top on incompetence. In some organisations obviously deliberately harmful positions are written into "policy". Often this comes under "PR" [fn:1]. More and more "AI" will be used to disguise malintent and deflect scrutiny.
In the final episode of the ITV dramatisation [0], Alan Bates (played by Toby Jones) delivers an absolutely shocking, knock down line. When talking about incompetence and evil he says: "They're the same thing" At some point there is no difference between incompetence and evil. For a deeper psychological discussion of that listen here [1].
[0] https://en.wikipedia.org/wiki/Mr_Bates_vs_The_Post_Office
[1] https://cybershow.uk/episodes.php?id=23 (from 39:20)
[fn:1] Edward Bernays seminal definition of public relations outlines a creed of deception, manipulation and disinformation which is antithetical to security [2].