It's a really good map for navigating at sea. The compass directions are always going to be accurate vs. something like the Robinson projection with accurate size but distorted shape.

Every projection is a compromise and a distortion. Globe is best :)

More to your point, is is probably the most popular projection -- even online maps like Google use a version of it -- so it is worth being able to recognize it and understand its strengths and weaknesses.

"...a Flemish geographer, cosmographer and cartographer. He is most renowned for creating the 1569 world map based on a new projection which represented sailing courses of constant bearing (rhumb lines) as straight lines—an innovation that is still employed in nautical charts." - Wikipedia

Basically it was really cool and advanced geometry in the 1500s. Other fun inventions of the time included bongs, rifles, and knitting machines.