You gotta be kidding, 9 bucks for 3 ounces of linseed blend? They probably bought that in 5 gal buckets for 50 bucks apiece and rebottled it at a 2,000 times markup. It's more economical bought in quarts instead. No, linseed is NOT a good camera finish, not unless it's been significantly modified using heat to turn it into a longer polymer chain called an alkyd, which should not be confused with merely boiled linseed oil. Back when I was a kid finishing walnut gunstocks with linseed, the effect of spending many hours hand-rubbing meant the heat of the rubbing friction was itself creating a longer, more durable fatty-acid linseed chain. That would be difficult to do on small camera parts. But who knows what is actually inside that tiny little bottle. The fact it can't be shipped to CA gives me a clue about the solvents involved. Don't buy any kind of traditional oil here - it's already been emasculated. But high-tech marine finishes, yes, as long as they're from an actual marine supplier. Of course, then you'll be paying high prices through the nose again.
Regular linseed breaks down fast and becomes microbe food. Also when I was young, I'd buy 55 gal drums of both linseed and paint thinner, mix em and add a decent amount of good ole carcinogenic pentachrolophenol to keep the microbes and mildew at bay, and use it as an exterior siding treatment. It had to be annually applied. Glad I didn't do that too many times, or I'd be long dead by now. Equivalent products, already factory blended, began coming out commercially about a decade later, equally deadly, until penta got outright banned from anything. More reputable manufacturers learned how to mimimize the toxics by starting with more stable alkyds to begin with. Linseed long-oil alkyds were especially good, but note the designation "long", significantly modified. These have since fallen out of favor due to air quality regulations. But in general, linseed long oils were chosen when something was wanted that took a very very long time to fully dry, potentially decades, or more correctly, to fully "cure"(technically distinct from mere solvent evaporation, but still with potential outgassing). Not what I'd want on a camera.