hell, I'd argue that it should be fine for formal writing as well. Ideally, the gap between written and spoken language is as narrow as possible, since ideally

hell, I'd argue that it should be fine for formal writing as well. Ideally, the gap between written and spoken language is as narrow as possible, since ideally a written text communicates with the reader directly, with as little hurdles to parsing the content as possible. Having to maintain a secondary vocabulary is exhausting and creates barriers. There is a limit to how permissive I am with this personally though, generally I'd only be happy with changes that are semantically near identical, or introduce words which represent genuinely novel concepts rather than slang that re-brands existing concepts.