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People tend to be afraid of the semicolon.
It's not that common, especially in informal writing. People don't feel confident they can use it "correctly"; I imagine many have been marked down in school assignments for it. Since it's seen as pretentious, there's a risk that using it incurs mockery as an uppity twit who got too big for their English britches. Sticking to periods and commas is the safer bet: they're harder to get really "wrong".
You know what I say to that? Fie!
People make grammatical "mistakes" all the time. It's just a fact of life. Don't let that hold you back from the full arsenal of punctuation.
It's vibes all the way down. There is an enormous number of --- equally intelligible --- ways to write any given sentence(s). If you're using punctuation at all, you're already going above and beyond; all you really need to write English is lowercase letters, space, and newline. If you're being a fancy-pants and putting in all that work anyway, why not take a chance on a semicolon?
I think of semi-colons as super-commas. You use commas inside a sentence to mash together different statements; you use semicolons between sentences to mash them together into super-sentences. "Super-comma" also describes the other way they're often used: to separate elements of a list which themselves contain commas.
Also, you can make a crying face with them. ;_;