The exact phrasing of some of these requests may have limited use; if you can’t remember what you had for breakfast yesterday, how are you going to recall that you listened to trap music three weeks ago. But the more open-ended options seem more likely to integrate smoothly into listeners’ language.
The focus on Amazon Music with these new Alexa developments is likely meant as further indirect encouragement from the tech company to have Echo smart speaker owners gravitate more towards its own music platform.