https://www.animenewsnetwork.com/interview/2018-01-17/the-producer-and-director-of-mary-and-the-witch-flower/.126544 interviews Studio #Ponoc ringleaders:

‘if this film ends up being more commercial – more welcomed by a broader audience, I must thank a certain girl, my daughter. After I had left Studio #Ghibli she told me, she said “Papa, I love The Tale of the Princess Kaguya and I loved Marnie, but why do you only make sad films? Why don't you make something more fun?” That made me realize that as her father, I wanted to make films that she would enjoy seeing.’ —Producer Nishimura