According to Chapter 1065 one’s Lineage Factor stores its memories and capabilities.
Now why exactly is this important? I’d like to bring you back to the time Seraphim Mihawk shaved off a considerable part of a mountain and made Blackbeard use Haki for the first time in the series.
The Seraphim aren’t inherently powerful due to the Lunarians genes but because of the Lineage Factor of the Warlords which helps them develop. The Mihawk Seraphim was able to put such a display of power because of the ability and recollections of the original Mihawk. Now the question is, if the Seraphim grows up, will it at some point acquire the power of the current Mihawk?
The second interesting detail is that Zoan fruits have a will of their own unlike Paramecia and Logia. We didn’t know the reason before but now we do. This is because Zoan fruits contain Lineage Factor of living beings and therefore are capable of retaining memories.
Zoan Awakenings often overhaul the personality of the original user causing them to become simple minded beasts (such as the Jailer Beasts). Same thing happened with Luffy during Gear 5. He lost all sense of fear and was overcome with joy but he still retained his original self.
Now what if he were to completely lose control over his self like the Jailer Beasts? If so, he’d turn entirely into the original Nika and maybe even retain some memories of the past as this chapter suggests. I can see Oda using this as a way to drop some important lore hints in the future.