What is the Point of the NBA's Second Bubble in Chicago?

The NBA and its players are gearing up for the season restart in Orlando, scheduled to kick off on July 30. Amidst all the tidbits of news about how the bubble will operate came the surprising report from Jackie MacMullan that the NBA was making a second bubble for the eight teams not participating in Orlando.

Yes. There will be a second bubble. In response to this news, I ask a simple question: why?

The NBA is closing in on signing off on a second “bubble” in Chicago for the eight teams that were not invited to play in Orlando, enabling mini-training camps and subsequent games against other clubs with a target date of September, sources tell ESPN’s Jackie MacMullan.
— Adrian Wojnarowski (@wojespn) July 2, 2020

In MacMullan's article, Dwane Casey had the following to say about why he wants his Pistons to be able to do this:

""The reason we want these mini-camps is to get our team together, to have that camaraderie, to improve and enjoy some competition. We feel we can do that safely in our own environment. We can't let these guys sit around from March 11 to December without something. It's going to hurt their careers. It's too long of a layoff.""
- Dwane Casey

I get that. I also think it might be a bit of an overstatement to say it'll hurt their careers in any substantial form since this is (hopefully) a once-in-a-lifetime situation and one weird offseason won't throw anybody off for longer than a calendar year. But while Casey's point holds weight, isn't there another, safer way to do this?

The teams that would participate in this second bubble feel left out and still have regional sports networks contracts to fulfill. There would be a certain competitive advantage even for the teams that don't make it past the regular season portion of the bubble at the start of the 2020-21 season. Even playing eight games of basketball is better than not playing any since March, which is what the eight leftover teams would be facing without this second bubble.

But Brian Windhorst said a month ago the players not playing in the bubble because their teams stunk would be getting the same pro-rated salaries as their colleagues in Orlando. If player money isn't an issue, how does that risk-reward balance out? Putting together a bubble is an extremely complicated endeavor, as anyone who's kept an eye on NBA news over the last two months can attest to. It comes with risk of coronavirus infection, a virus so deadly it shut down the world. It still runs rampant in this country. It's an immense risk to put eight teams' worth of personnel together without a big upside from where I'm sitting.

Putting everyone under one roof has its benefits, but with all the complications and bigger risk of widespread infection, it's fair to wonder if it's worth it.