I think if we're talking about a game for the four teams (two in each conference) who lost in the first round of the playoffs, there's some merit. Basically, they're paying a full week's salaries and only gaining a half a week's worth of arena revenue, which does diminish the value of making the playoffs. Giving them a second game that week would help, though I would also suggest that the attendance should be lower for the 'consolation' game than it would for a regular playoff game to ensure that winning the first game is more valuable than not.
If we're talking about a game/series between the losers of the conference finals, that's not really worth doing. Teams would still have to pay player salaries, which could lead to a negative economic impact for teams that are on a roughly balanced budget since they're paying full salaries again, while teams that buy and sell for playoffs will just sell their high end players, have a low wage bill and get the extra revenue.
I think the suggestion is more in line with the first option, and I think ensuring that a team that makes the playoffs with a fairly balanced economy should not lose money by doing so is a good thing.