#2 He is a massive upgrade on all Manchester United defenders
Beyond the international experience he will bring to the United back line, he is also flat-out a better defender than everybody in the current Manchester United defense.
For the last three seasons, Toby Alderweireld has been one half of the most consistent centre-back pairing, along with international compatriot Jan Vertonghen.
Together, they helped Tottenham achieve the best league defensive record in the club's history in 2016/2017, with only 26 goals conceded in the Premier League (only 9 of which were conceded in home league games) and was 6 better than the previous record of 32 conceded that was set over 100 years earlier in the 1908/09 season in the then second division.
They also had the best defensive record in the Premier League during Alderweireld's first season at North London, conceding only 35 goals in the Premier League, with Alderweireld being named into the PFA Team of the Year for that season.
His addition to Manchester United would markedly improve the Old Trafford defense, as he is a palpably significant upgrade on all the first-team defenders at Manchester United.