Cheaper + more physical play style. And if you can't sign him in 2023 then trade him to someone at the TDL? He's less talented yet still has 60 points in 67 games for a terrible Detroit team. I'd argue that Fiala isn't hitting 80 points in Detroit and that his production would be closer to 70ish points. And you could bank on Bertuzzi scoring more in Minnesota with better talent around him.
Who did Bertuzzi play with ? Larkin? Raymond? Cause Fiala was playing with victor Rask, Nick Bonino, Marcus Johansson, Nick Bjugstad, and worse, for the majority of his time in MN. The center he is playing with now, F. Gaudreau, was a 27 yo starting the season, with a NHL career of 18 pts. in 108 gp.
Since Boldy started playing with him, he is playing at a 1.5 Point/per game pace. 63 pts. in 44gp.
You can argue that MN held Fiala back( keeping him off the main PP till recently), and that sticking him with Raymond, and/or Larkin, would increase his output. Larkin would be by far the best Center he has ever played with, and Raymond is Boldy's equal, IMO, if not better.