1. Most all knots shake loose, even a buntline or a constrictor can loosen when shaken severely. Bowlines are notorious for shaking loose.
2. Splices are much stronger than ANY knot, the strongest knot is probably the Carrick at 80% breaking strengh of the line. Splices approach the full breaking strength of the l ine.
3. Problem with splices is that the chafe will be solely at one single spot (dead center in middle of the eye); with knots you can adjust and retie for chafe. With knots you can keep trimming back into unchafed line. Chafe with splices can be lessened by ''taking two turns'' on the clew iron instead of a simple eye splice. ..... inother words the splice is wrapped around the clew iron a second time to distribute the load and reduce chafe.
I prefer a single sheet (double length) with the line reeved at the middle to the clew. The knot is either a clove hitch or "constrictor" --- small sized knot, adjustable (with difficulty) for chafe. The larger the D-ring or grommet in the clew, the less the chafe.