I’m sure it is to many. For anime movie watching, it was sandwiched between Sword Art Online Progressive: Aria of a Starless Night and Your Name. in viewing order. Those two were more to my tastes.
If you’re going to travel back to the past, you’re going to do so to see some unviewed painting, play baseball, and crush on some girl? You could meet someone famous, cure problems in the future, get insanely rich, etc.
And time travel is so common in the future that this kid has it? He’s so irresponsible that he loses something that could be used for evil purposes.