You wouldn’t start off an e-mail with “My Dear X”, or “Dearest X”, since that would be too personal for a professional email, so “To X” being more impersonal seems like it would make the letter more professional-sounding, compared to “Dear X”.
You wouldn’t start off an e-mail with “My Dear X”, or “Dearest X”, since that would be too personal for a professional email, so “To X” being more impersonal seems like it would make the letter more professional-sounding, compared to “Dear X”.
“Dear” to someone you aren’t familiar with has a slightly different purpose I think, it communicates that you’re seeking the recipient’s mutual participation in a social group by engaging with your communication. You acknowledge their position of being ‘dear’ to general society to positively reinforce their participation in it, specifically with regard to your letter.
These days it’s fairly trivial to contact pretty much anyone about any matter. Being more connected we are continuously engaged, so it sounds funny/out of place to use in an everyday context. You could use it sarcastically to imply that the recipient is careless or doesn’t like you (they need encouragement to engage in communication generally/personally with you).
But it would still be appropriate in a context where the recipient is hard to contact, like a public or official person with whom communication is sought after