What criteria does it use to decide which visual design pattern to use?
So Tableau is difficult because it's an all-in-one package with a lot of moving parts...and I rarely need all of those moving parts. While I don't use Tableau myself, I know many people who do, and generally they use it because they don't know how to do web things, period...i.e. Tableau's web charts "just work", once you learn how to build them.
Of course, "just works" is a moving target in this day of responsive web and AMP and non-Web platforms (i.e. Facebook Instant Articles)...media publications that produce Tableau viz are going to have to find a workaround, or hope that Tableau continues to innovate in making their viz packages portable.