I have a love-hate relationship with writing and receiving thank-you emails. You know those emails... where the only text in the body is some version of "thank you".
These messages add one more email to process in an already full inbox.
Do you delete the email or reply with a "you're welcome"? This just adds to the clutter.
Do you archive the email? What do you do with an archive of thank you emails? No one is browsing their Outlook application in their free time!
When I receive a thank-you email, I read it and delete it. Thank-you emails do not get archived away in my inbox. They get processed, which is reading, then deleted. Not because I hate those emails -- I do not, but because the intention is conveyed as soon as I have read the words thank and you.
And if you have sent me a thank-you email, I appreciate you doing that. You are very welcome.
But here is why I send them...
The infinitely cluttered mess of social media platforms makes it very easy for one to acknowledge another without having to type words. Typing words makes people read words and adds further clutter to an already full message notification bar. In social media, you can hit the little like button, heart icon, favorite icon or whatever your app allows. No need to write a comment. Acknowledgement done.
Traditional email does not allow any such button other than a mark-as-read notification which are tacky to say the least. So I tend to reply with a "thank you", but I also add something like "perfect, that helped me". This shows that not only did the sender send me what I requested, but their help was meaningful to my project.
These few extra words in addition to the "thank you" really emphasize the value of the work that was done. A simple "thank you" is just saying,"you checked the box you obedient little widget".