One of the strong reasons may be because Vincent Company was once Pep Guardiola's assistant so Bayern Munich thought they wanted to try his coaching system and use strategies like Pep's and Pep has also said that he has the ability to lead if he is supported by great players.
Bayern Munich already has great players in it so he can use all his abilities to strengthen Bayern Munich next season. Apart from that, there is great hope that he can restore Bayern to its former glory when leading the Bundesliga without any club threatening Bayern at the top anymore.
The club that can still be a serious threat to Bayern Munich is Bayer Leverkusen because the club will still be coached by the same coach so the strategy will probably not be much different from last season, although some may be changed to make it less easy for all opponents to read. I also think that Vincent Company has the ability to train Bayern Munich's players next season, but this will also be quite difficult for Vincent Company because considering that Bayer Leverkusen can still be better than last season in the Bundesliga next season.