Why Do Shirts Have a Horizontal Button Hole at the Bottom?

The question isn't as sideways as you might think.

Why, on most men's button-down shirts, is the bottom-most button slit horizontal, not vertical like the rest? - Quora

UNTUCKit Mens Blue Horizontal Striped Shirt Slim Fit Button Front Mens Large

Competitive Pricing Whats The Difference Between Button Up And

How to Make a Hand-Stitched Buttonhole – Twig + Tale

Why is the lowest button hole on a dress shirt horizontal, while all the others are vertical? - Daily interesting stories and facts - Quora

Why Do Shirts Have a Horizontal Button Hole at the Bottom?

Competitive Pricing Whats The Difference Between Button Up And

Button Hole Machine: Parts, Specification and Working Principle

When did they stop making horizontal button holes?

Further Details