I guess it depends if you’re a glass-half-full sort of person or not.
In one case, sure, it shows you a price you can’t get unless you buy 24 months. On the other hand, it shows you that there is a sale on and what the lowest Plex cost you can currently get is.
Some people will see it either way. Just as a side-note though, CCP has a long-standing habit of choosing really odd ways to display information (or conceal it). It’s always best to double and even triple check things before making decisions.