Until I lost that anchor yesterday, I thought your aforementioned reason was
*the* most important reason for rode. Now I see both reasons (prevent
strafe and reduce the pulling angle) are equally important.

The more chain you use, the less scope you will need in almost any situation.

If you routinely anchor in relatively deep or crowded areas where 5 to 1 is
impractical,
an all-chain rode will often hold as well at 3 to 1 as a rope rode will at 5.
The extra weight of the chain keeps a shock absorbing "belly" in the rode to
help resist pullout, in addition to a more horizontal, (less vertical) pull on
the anchor once it is set.