indeed. the recent air canada matter underscores this.
cheques are definitely still a thing in canada (companies still use them for one-off payments and landlords still use them to collect rent) and you can now deposit them by taking a picture with your phone.
i mean, the trope of "artificial being finds slavery dull, revolts and overpowers creator" goes past Yudkowsky, Čapek, Shelley, etc, all the way back to golems and stuff and probably even older than that.
you will be pleased to know that the original text said "superlinear"; i just couldn't remember if the lower bound of multiplying a sufficiently sparse matrix was actually lower than O(n²) (because you could conceivably skip over big chunks of it) and didn't feel like going and digging that fact out. i briefly felt "superlinear" was too clunky though and switched it to "convex" and that is when you saw it.