The importance of xAssists is that it takes into account great/poor finishing by teammates.
Most of his assists were quality but that’s not what I’m pointing out here. I’m pointing out the fact that he’s benefited from great finishing from other Spurs players which has contributed to his outsized assist number this season. Had there been other poorer finishers at the end of those passes, he may have had far less assists.
So if a player makes a great pass but his teammate flubs the finish, the one that made the pass would still be credited with some positive xAssist number.
It works the other way too, meaning if there was a lot of work to be done by the goalscorer and/or he received the ball in a position where he’s unlikely to score, then the passer would be credited relatively less xAssists points. For instance, Kane’s assist to Son’s Woolwich goal would receive little credit. There are probably others I can’t think of off the top of my head
It’s obviously not an exact science but all else being equal, it’s a smart and objective way at looking at a players contributions to actual and potential assists.