I did not know that, so officially my kid should not have it's own account.
Still that doesn't make it better in practice. Spotify is able to predict average age from listening behaviour. I was recommend the 'Dad's music' playlist last week :)
They know your age, and they could use that for something positive.
And what incentive do they have to do this?
It's easy for a tech company to say it's not their responsibility. There is a disclaimer and some 'terms and conditions' so you meet your legal obligations.
Spotify is allowed to fill kids heads with dirt, dirt which no record label would ever publish, and no kid would ever hear without streaming media.
Legally it's fine but it feels shallow and poor. I guess it's the reality of stream and social recommendation algorithms.
Use the services they provide that are specifically intended for kids under 13.