Arguably, it was better for Allen to become a Perfection Realm powerhouse early on so he could get used to his power and build up his foundation but Allen didn't have any more motivation as yet to become one.
Allen was already the strongest in his world and he didn't face any threat that has surpassed him.
Also, he wanted to procrastinate in keeping his humanity a bit longer since he knew in the future, he had to give up his humanity.
For other people, they would think that what Allen was doing was just delaying the inevitable and that it was best for him to do what he should be doing rather than delay it.
But Allen knew that if he became a Perfection Realm powerhouse, his mindset might become completely different from what he had before.
