I'm not sure what the swivel is supposed to do in an anchoring, as opposed to mooring, situation. If the wind shifts 180 degrees the anchor
will (I hope) reset. The twisting that a swivel is supposed to eliminate is not a big problem with anchor
use because: 1) it is short term,and 2) the anchor
should reset, reducing or eliminating the twist.
A mooring, which is fixed and long term, is of course, another story.