Why the cocktail umbrella?

What’s the thinking behind the cocktail umbrella? I know the only purpose is decorative, but why an umbrella? And it really should be called a cocktail parasol. They are fun and I kinda dig them in my boat drinks, but does anyone else find the idea of an umbrella in your drink weird? I believe they originate from the original tiki bar and home of the Mai Tai, Trader Vic’s, and have been around for many decades. I just noticed that I have a bag of these umbrellas in my liquor cabinet and boredom has me asking about them.