He wasn’t “advised” to join Spurs. He wants to join Spurs. He is capable of making his own decisions, you know.
He was shown around the new stadium and the training ground and was, understandably, deeply impressed. He met with Pochettino and was equally impressed. He knows that Spurs have qualified for the CL for the past four seasons and that they were CL finalists last season.
Above all, he knows that Spurs have been his most persistent suitor over the past year and a half; that they want and need him very much; and that they aren’t merely stockpiling players just because they can. He knows that he will be a starter. He needs and wants to test himself in one of the two strongest leagues in Europe - Premier League or La Liga.
At what other club, that could afford him, would he get all of the above? Of the clubs with better immediate prospects in the PL, neither City nor Liverpool could offer him anything like as certain a starting role. Likewise Barca and Real in La Liga. Atletico could perhaps have done so but they have just bought Llorente.
All told, I think Spurs under Poch is the perfect club for him to continue his development. He’s only 22. Madrid or Barca can wait.