Which ChatGPT likely "always does" because the vast majoity of style manuals prescribe closed usage[1][2][3], and that's therefore how it mostly appears in human-generated text. It's definitely how I learned to use it long before LLMs existed.

[1] https://en.wikipedia.org/wiki/Dash#Spacing_and_substitution

[2] https://www.merriam-webster.com/grammar/em-dash-en-dash-how-...

[3] https://learn.microsoft.com/en-us/style-guide/punctuation/da...

Yeah. Between that, the circled numbers, poor spacing, actual use of ±, odd choices of language and the brand new account, I think you're right that it's a bot.