Golds are not a ton better for upgrades than Silver (which tend to get upgraded only on weird outlier flights).

If you're flying Main, it's nice to get priority seats (if available) for free and slightly nicer to board in whatever they've replaced "sky priority" group with--at any rate, in advance of "lower-status" Main passengers. (Nothing against them but I do think the PMs/DMs who will be in Main ahead of you tend to be more experienced fliers with more familiarity with the Delta setup, meaning less waiting in the aisle for someone else to figure out how an overhead bin works.)

Gold gets you lounge access when flying in F to/from Canada--an obscure perk, to be sure, but one that happens to sometimes fit my personal flying patterns.