IANAL. As a contributor? It means the company can relicense my contributions into a license that is wildly different from their current one (including no license/copyright). It affords me no benefit.
There are CLA alternatives like the Developer Certificate of Origin (DCO) that ensure the company has the "legal standing" to accept a contribution without infringing on copyright, but it doesn't give them the ability to relicense.
Sure they could relicense it to something wildly different, but they can't retroactively take back old versions of it, so you can still run it as it was when you made the contributions.
I wish nobody required CLAs, but I'm glad that there are products like Cal that would (assumedly) be closed contribution otherwise due to (real or perceived) legal risk.
It means they can sue for open source license violations on your behalf, something that's a bit harder if they don't actually wholly own the copyright.
