Movies & TV

So idk what the exact prescriptive rules are, but the way I've always used the ampersand (and have seen it used) is to make it easier to parse a sentence that's like

I need to talk about spelunking and skydiving and scuba diving is scheduled for next week.

While this would probably be clear in speech from prosodic cues (e.g. pauses and emphasis), in writing it's not obvious where "things to talk about" end and "activities scheduled for next week" begin. This ambiguity can be cleared up by an ampersand, which is used to group two items together but is not used as a conjunction for introducing a new cause. So if I replace the first "and" with an ampersand like this:

I need to talk about spelunking & skydiving and scuba diving is scheduled for next week.

it becomes clear that "spelunking & skydiving" are the things I want to talk about and "scuba diving" is the scheduled activity. Since I know that & only serves the function of grouping two bits together (nouns in this case), as soon as I hit the "and" I know that it's the beginning of a second clause. Ampersands can be useful even in a case which isn't ambiguous, like

I need to talk about spelunking and skydiving and I would also like a taco.

"Skydiving and I would and also like a taco" is obviously not a plausible interpretation for the second clause of the sentence, but even so, there's still a tiny bit of extra work your brain has to do to parse the first "and" as an item-grouper and the second "and" as a clause introducer. Using an ampersand in place of the first "and" makes things a little easier for the reader.

I'd guess that in a professional writing scenario it's probably better to rewrite the sentence to avoid ambiguity rather than leaning on the ampersand, but if you're just writing a comment on the internet who's got time for that? Oh, and obviously in less formal situations people might just use & just for the hell of it, but that feels kinda boomer-coded to me. For what it's worth, the tweet in question is exactly 280 characters so it's probably just a Twitter word limit thing.