Out-of-universe, the DS9 jumpsuits were the current Star Trek
In-universe, commanding officers seem to have the authority to decide which uniforms the crew will wear. Janeway liked the jumpsuits, therefore the jumpsuits were the preferred uniform for all.
In DS9, when Sisko becomes temporary head of Starfleet Security on Earth, he wears the TNG-era uniform. It seems to be a more formal uniform, between the dress uniform and the "fatigues" of DS9. Would make sense for Picard to prefer a more formal uniform for his starship.