Ellipses as pauses is a leftover of telegrams which bled into the era of limited text messages(and/or charging by the text), because the financial incentives for long single messages were the same.
In the era of unlimited texting, though, we’ve dropped that convention because it’s extra keystrokes. In fact, we’ve even dropped the period at the end of sentences in texts because you can just hit the send button as a thought separator, sending multiple texts.
Including the period is unnecessary extra information, so it is seen as formal at best or even a way to covey unhappiness, anger, or frustration.
Hope this helps! Note that none of this applies to longer form messages like this one.
hit the send button as a thought separator
This drives me nuts, that’s what blank spaces are for. I don’t like getting a half-dozen texts that blow up my phone, especially when I’m likely in a meeting or something. A text message should be a complete communication, with blank spaces to separate parts of the message.
For example:
I’ll be home late tonight, the meeting went long. Should be there in 30 min.
BTW, should I pick up something for dinner?
My SIL would send that in like 7 texts somehow, whereas I’ll send just one. I find it impolite to send so many, so I go out of my way to spend a few extra seconds making it nice for the other person to read.