The 23-year-old joined Spurs from Sporting Lisbon with a reputation of being able to play in a number of roles, including both in defence and midfield.
"We took a big risk not signing another midfielder and it was fantastic," Pochettino told reporters. "He deserved all the praise and our decision [paid off] to be brave and give him the possibility to play in a club like Tottenham when you fight for big things."
Asked about Dier's utility-man status, which saw him play 48 times for Spurs and a further eight times for England in 2016-17, Pochettino added: "If he in time shows he is great or one of the best in the world in one position, OK, that is fantastic for him.
"But if you are a very good player and can play very well in different positions, there are more possibilities for him to play. I think the most important thing last season was that he was the player in the squad that played the most. When you are a player, you want to play and be in the starting XI.
"He can dominate different positions on the pitch and that is so fantastic - he can be top as a midfielder, centre-back or full-back. Then it is up to the manager to use him in different positions."
Dier has featured seven times for Tottenham already this season, including a 10-minute cameo from the bench against Barnsley in the EFL Cup on Tuesday night.