You could argue this isn't intentional on Yousician's part, but they have done nothing to change it. They are obviously aware people are confused about the model, but don't do anything to fix it.
I see people argue that it was right there on the page when you signed up. Based on app reviews and forums, a lot of people are confused about the model. I almost fell into the trap myself when I signed up for the 7 day trial.
I understand, Yousician is a product that is meant to be profitable. The business model should focus on the merits of product and its marketing. Not tricking people out of their money. I am a subscriber to Yousician. I want to support the product, but I cannot recommend it to my friends. I don't want them to get taken for a ride if they are not careful.
So why is the model so confusing? When you go to sign up or start a free trial, you get a pricing page. Your eyes are drawn to the $10/month and the $15/month and not the small text at the bottom or the awkward toggle at the top. Also, with all of the subscriptions out there, we have come to assume that it's cancel at any time (for consumer products). Anything else seems outlandish.
How can Yousician fix it if they cared? Put all four plans on the same page. Get rid of that toggle. Make the annual subscriptions read '$/year' and not just the small grey text at the bottom. Slap a big ol' 'SAVE 50%' on the annual subscriptions to make buyers aware of the savings and understand the choice they are making.
This has been an issue since I first checked out Yousician, people complain and nothing has changed. This is my plea, do the right thing. This model feels malicious and makes me resent an otherwise great product.