To play advocate of the devil here (I can feel the down votes and Foss brigade already coming) : I can understand their logic. Their whole business is fucking ads. These apps bypass their entire business. Count yourself lucky they've ignored them this long.
YouTube premium is actually one of the only subscription services I use. My entire family gets ad free YouTube + YouTube premium. The amount of YouTube we watch and music we listen... 100% worth it. + a premium view supports creators more than a free view, so I even get to feel a bit better about myself. (I watch too many different channels to make it financially viable for myself to send them all a dollar/month through means outside of YouTube)
Those are amazing. The painting one would require a math degree to plan out correctly ;)