So far, the biggest thing that has relevance is the fact that, he actually transitions back in forth between the present and future versions of himself in an attempt to change the future. At the moment, the two biggest reasons are to get Haruka's mother to accept their marriage. She is that standard high-class bitch that thinks unless the mc is someone "important" he's not good enough for her daughter. The second is to help Haruka's father. Her dad owns a fairly large company and in the future, it goes bankrupt. This, in turn, makes it so Haruka's sister needs to live with them, parents no longer live well, etc. In fact, him saving the company is his best bet to get Haruka's mom to accept their marriage.