What IS frustrating is that some of their products don't offer a monthly plan. I want to use Lightroom about once a year, after going on a big vacation, but there's no cheap plan that just includes Lightroom.
There's a $10/month annual Photography Plan that includes Photoshop and Lightroom (exactly what I want), but no monthly option. I would pay $15 for one month of this, but the only way to get Lightroom for a single month is with the All Apps package, which is $80 for a single month.