He's just emphasizing the amount of creativity you need in mathematics research.
I’m a bit cautious about this because it’s presented as “he is said to have remarked…”, but cutting people down - especially students - to make some other point is unnecessary and not ideal.
not that I particularly like Hilbert, he gives me a bad vibe because:
how do I forgive shitty professors who have refused to help me? how do I let go of the fact they are awful people from a different era? How do I refuse to undergo the rituals which teach things I whish to not learn (certain attitudes) while at the same time making it through those same rituals I reject?
and it turns out the professor I speak of IS on D. Hilbert's lineage!