Indeed Allah (swt) as the Creator has the power of Kun Fayakun, but the creations take their own time to develop. Laborers can build a 10 storied building in a week's time, but will this building have the sustainability and durability. So the lack of durability is because the structure did not get enough time to strengthen. Hence, to give it sustainability and robustness and long-life, laborers give enough time for and after each stage. Thus, these six days are actually the six stages for the universe to evolve and to garner sustainability. Allah (swt) can bestow any creation with inherent, inbuilt and natural knowledge like it has done with birds and animals, etc. A young chicken that has just come out of egg shell knows what to eat and what not to eat. It also knows that it has to be safe from eagles but not from humans. Whereas a young born human baby does not even have that elementary knowledge. It has to be taught each and everything. Despite that Allah (swt) has taken pride after creating man and has referred to in the Holy Quran as 'Ahsanul Khaliqeen' (The Best Creation). Why? Because, he has let man evolve steadily. As man acquires knowledge and wisdom he can tear through the skies into the space and into the depth of the oceans. He can aspire for greatness more than the Heavenly Angles. On the other hand, the inbuilt knowledge of birds and animals remain static.