Is there any language where the meaning isn't immediately clear? I haven't seen a language that didn't differentiate between '<=' and '<'. The syntax of just '..' is a little unclear at first however, but it is simply a requirement of learning the language and the idioms

it's not. i've never used swift, and the meaning was instantly obvious - i'd call that a very elegant solution to a common problem i've seen in several languages.

Read it as "For 0 to count" basically. "0... (spread operator) less than 0. It seems confusing to me as well at first read but I'm used to writing for loops by hand uphill both ways.