When Luxee started A69, he explained that the game is not supposed to be a classical sandbox. He uses the sandbox elements present because he felt they were a (not necessarily the best, but the one he came up with feeling comfortable with) solution for him writing the story in a way that kept him in the loop.
You won't have to grind or browse through places to find events or any of that, but he explained that in the confines of a classical VN, he felt compelled to write everything as it happened, including a lot of filler stuff, that was just there because he spelled out everything from A-Z, not because it was overly important or interesting.
He wanted an option to concentrate on the important/interesting scenes without all that filler, and he wanted to be able to write at what he felt inspired for - whereas in a classical VN, he would have felt compelled to write whatever happened at the point in time he was at, just because that was where the story was at, without options to write other stuff and then fill story holes later.
So with the current way, you always know where memories are available, you only get the memories important for the story, and Luxee can work at whatever memory he wants without breaking story flow or continuity because they aren't part of a fixed chain of events/timeline.
You can like that or not, and Luxee himself admitted this might not be the most elaborate solution and not even a problem others deem worthy of being addressed/fixed, but he felt it was the best option for himself to address his 'me-problems' when it came to writing the story of A69.