Purdue is likely at worst a 5 seed, and probably at best a 4. The path through the tournament isn't much different for those seeds. This game won't have a serious impact on that, and Purdue's BTT run will have a much bigger impact on where they end up. An injury to one of their key players at this point in a "meaningless" game for them could seriously impact balance of the season. They already have the conference championship locked up.
Purdue ain't resting players, that would be ridiculous. Like, by that logic Northwestern thinks this game is meaningless too cause we've locked up our tourney bid and can't win the conference title? That's ridiculous. There are only so many games in the CBB season and every single one is important, not the least of which for postseason seeding. Purdue is playing for a top 16 spot which gives them regional preference on location, and maybe a 3 seed which would significantly improve their path.
If you want to stretch you could probably infer that they will be a bit less desperate to win than if they hadn't already clinched the conference title. But it's still the last B1G reg season game for their team, some seniors, and they are on national TV where a lot of tourney voters will be watching. No one is resting starters here, and they will come ready to play. We just have to come ready to play better than them.
Go Cats