Here's my thinking.
First, Buxton is not just the Twins best player, he is a truly elite talent in a sport where you don't have many. For his career, he's averaged over 5 WAR for 162 games.
Second, the Twins can afford him. Fans have been conditioned for years to accept that the Twins are a small payroll team, that they can only afford so much, that paying Mauer hampered their options. It's all BS. The Twins are loaded and have, like all teams, refused to share their books with the player's association. It's insulting that the management has allowed fans to believe that players should give "home town discounts" or blame players for payroll crunches. Even if we believed the FO spin on payroll, the team spent years, decades even, playing under the potential high payroll while they were reloading, rebuilding, etc. They have never spent a similar period of time over their expected payroll. Fans should demand they do.
Third, historically, MLB teams that trade away truly elite talent usually lose those trades. This isn't a Liriano for Escobar trade. This is getting rid of a HOF talented level player in his prime.
So I don't really understand anything other than "sign him and keep him." Sure, he might get injured. Maybe. That's the risk. But it's just money at this point. Money the team has and should be using to put the best product they can on the field.