The pros and cons of different operator possibilities are discussed extensively in the PEP that added the matrix multiplication operator.
> APL apparently used +.× , which by combining a multi-character token, confusing attribute-access-like . syntax, and a unicode character, ranks somewhere below U+2603 SNOWMAN on our candidate list.
and then later, one of the reasons @ is better than the alternatives:
> Whatever, we have to pick something.
(Aside: HN really needs a better way to escape star inline in text.)