What is the psychology of playing ellipsis like this when sending text messages?

It's nothing. It's just that everyone's habits are different, and the usage of each mobile phone is different. It is more likely to press which punctuation mark is easy to press.

If a sentence is separated, some people may be used to using commas, some with exclamation marks, some with ellipsis, and some with spaces. Many of them are general habitual problems.