إِمَّا لِأَنَّهُ الْأَصْلُ
Or because it is the original or usual arrangement.
The musnad ilayh is the referent to which a judgment is ascribed. Stating it first is therefore the unmarked arrangement unless a purpose calls for departing from that order. This is a rhetorical rationale for order, not a rigid psychological claim about which concept enters the mind first.
«العِلْمُ نَافِعٌ» naturally presents knowledge and then predicates usefulness. Without contextual evidence, it need not mean that nothing else is useful.