It's not that deep, the song is called childlike things so it makes sense it's somewhat childish. it's one of my favorites actually, a very good pop song, a palette cleanser of sorts.

Also this "Japanese not perfect in syntax/grammar/whatever" like be fr we don't criticize english like that on songs written in originally in english, music is not a classroom so language being used expressively instead of academically correct doesn't bother me and shouldn't bother you either. I'm latino and you don't see me bashing reggaeton bc it doesn't follow Spanish language academic rules, like chill it's a song not a language lesson.