Just because they can't decrypt it now doesn't mean they won't be able to eventually. The Utah data center is storing a lot of encrypted internet traffic with the expectation that it will be decryptable at some point.
Projected to be within the next couple of decades using quantum computers, I believe, although obviously there's a lot of uncertainty in that estimate.
Metadata is still very useful.
Any channel that really cares about eavesdropping transmits constantly, at the same rate, mixing real encrypted packets and random data to keep the bit rate unchanged.
This, of course, eliminates any possibility to share the bandwidth with any other users, so it's more expensive.