Difference between Spackle and Drywall Joint Compound

At first, I did a double take on reading the OP's post, because I have used them interchangeably (and without realizing there even *is* a distinction!) for decades. OTOH, the article may help explain some anomalous results I've gotten over the years. I think the best summary came later in the article:

"Got a tub of joint compound left over from a previous renovation? Feel free to substitute drywall mud for spackle for small drywall repairs. Just be aware that joint compound runs the risk of shrinking, which calls for multiple coats and a longer dry time—sometimes up to 24 hours."

I definitely *have* experienced variations in drying times, and in the amount of shrinkage after drying, sometimes requiring multiple coats in situations where I didn't anticipate the possibility. The article was helpful in laying out the distinction between them (my thanks to the OP!), but my takeaway is that, for large-scale landscape construction, one would probably be best served by using a purpose-formulated product like sculptamold rather than a product designed for patching seams or small holes in gypsum board.