CCA is more brittle than pure copper and some say will deteriorate over a shorter time.

I use it for some hobbyist stuff (not networking), but wouldn’t pull it through a wall or in a place that I wouldn’t want to go to again.

I don’t think that the cable you referenced is pure copper, since the vendor lists very little about the actual specs. If it were pure copper, it would be listed.

If 8ware is your go to vendor, this is the only bulk cable that I saw, that was listed as pure copper. It’s more than you need, sadly.

As to the purpose of the drain wire: It provides a more reliable ground connection at the plug over only a crimped foil connection.

There’s a customer question that the website answered, they said it’s a solid cable. So it sounds like it is pure copper.