Actually not a bad idea for guns that have manufacturer lifetime warranties. Gander matches manufacturer, so in the case of lifetime, Gander's coverage is also lifetime.
Sometimes the manufacturer won't cover incoming shipping. If this happens just once, then that will cost you roughly the same price as the protection plan. With Gander, you just drop the gun off with them, they deal with the shipping no matter how many times it goes in. When it comes to lifetime, you also have no idea what the laws in the future may hold. Maybe somewhere down the line, 'unlicensed' people can't ship guns themselves anymore, even through UPS/Fedex. There's a possibility that happens in your lifetime.
While I'm usually one of those cynics when it comes to such protection plans, I don't think it's a terrible gamble to pay $30 for a literal lifetime of complete coverage (shipping, parts, labor, replacement, etc).
I've known of some gun manufacturers that used to have high praises sung from the hilltops about their customer service being generous with return shipping labels. Currently, S&W is one of them. But I also know of some that used to be that way, and have tightened up their budget, and you can't rule out S&W goes down that path within your lifetime.