(adding your tags since I'm addressing them)
It’s polite, for one. Professional doesn’t need to mean elaborate—in fact, most professional emails are aiming to be as clear and concise as possible. (in english at least, I know some other languages have some very complicated and elaborate email etiquette)
Greetings and signatures also don’t need to be elaborate. I feel like lots of people overthink it and assume that professional emails need the whole “dear x, my name is x and I am writing this email to inform you about [topic], sincerely [my name and all my contact info]” shebang, when really it’s as simple as adding a quick greeting/signature and avoiding super informal slang.
Here’s an comparison using art commission inquiry as the topic, written with zero extra fluff:
Hi,
Are you currently open for commissions?
Thanks,
[my name]
If I want to add a little more fluff, maybe I write:
Hi,
I love your art and wanted to ask if you're currently open for commissions. Here are details of what I'm interested in. Thanks for your time!
Thanks/best/etc,
[my name]
Those are very short while also being more polite than an email that just says:
with zero greeting/signature and very informal tone.
There’s still a person on the other side reading that email, and just like how being polite with a customer service agent on the phone will get you better results than being rude with them, sending a clear and professional email will have you taken more seriously by whoever is reading it. All 3 emails get the same point across, but the last one leaves a much worse impression. You don’t speak to your close friends the same way you’d speak to strangers, and it’s the same in text form. I get so many emails that are just abrupt questions, with not even a quick "thank you" either in the initial email or as a follow-up after I respond, because they ghost me as if I'm just a chat bot answering questions.
I know complaining about email language sounds like a ~corporate america white-collar bullshit~ kinda thing, and there is indeed significantly more elaborate email etiquette that can vastly differ depending on your job/field that I’m not addressing at all, but just having the very basics goes a long way in how your emails are viewed by other people.
