In practice, you'd think a patent would be useful, if you had a novel idea, and wanted to make a buck off it. A few "minor" extensions to property law and whamo, now only YOU can profit off your novelty! Well, why not! A guy's gotta eat, and it fosters the friendly and fair competition that makes markets efficient, eh? Well maybe, but that was then and this is now, and if your not a mega-corporation and that's not a cash cow, patents are useless, unless 1. your idea is good enough and easy enough to steal and 2. can afford the legal team to go with it, and most importantly 3. you prioritize vengeance and that almighty dollar above all else. Well you might stop a corporation from stealing your wares (yeah right) but more likely you'd have nothing for it but some empty pride, and would only be able to give a small time foe a short fight.
As a comparison, is Justin or ebikes.ca patenting anything, as a small scale producer? His stuff is not open source or anything (shame shame!), but anyone could knock those creations off - I mean most of it is just building on the basics, so why don't they? They offer a refined product and the service to match, and they've built a reputation with the community they serve. That's the best protection I can think of for "physibles" - and it's basically free. Tesla opened up their patents, why? Because they get in the way of some important things, like market adoption and standardization. GNU/Linux runs a giant, outsize portion of the world, why? Because it's not obstructionist, people with brains can move at the speed of thought and leave the lawyering to the already-rich Luddites waiting to die. They licensed it specifically to give corporate greed monsters a massive headache, and it's worked so far!
I've got some engineer buddies that went to the trouble over the years to patent some kind of fairly inane, marginally interesting crap (the few old timers that didn't have to sign workplace intellectual property waivers), and for all of them, there are one of two outcomes: You have something to brag about when giving lectures and at cocktail parties, and/or two - they have something to be bitter about for the rest of their lives after Dong Xi Widget company knocks it off. Engineers aren't the poorest of folks, but a patent battle with a trans-national or a foreign entity is not even remotely in the cards. Unless you are on a mission to stifle small business or starting a professional patent troll firm, I'd say don't waste your time.
Everybody that likes to tinker raves about 3D printing, CNC milling, free software, DIY 'lectrics and the new "maker" revolution, and we all share ideas with our techie buddies on forums, while corporate pigs are busy toiling away, trying to put the genie back in the bottle with ridiculous fairy tales of Digital Rights Management and stronger, International Intellectual Property rights dressed up as free trade. Started with the entertainment industry, and they still prattle on with their unworkable schemes about "owning" ideas.
Dauntless' comparison of remixing music to stealing 2x4's is, well... frankly laughable. While stealing goods is a tangible thing, and he got deprived in the act of that theft, people remixing Beatles' or Carters' or reworking such tunes deprives no one of anything, we're all richer for it. Ideas, knowledge, creativity - these are not a zero sum. No one is going to buy the Grey Album if they wanted the White one. The very notion that an idea can be "stolen" is ridiculous. Heck, one person walks into a library and steals all the ideas, locks it away in his head and damn - we'd all be better off dead! Not to mention the fact that the poor dead Carters and Beatles of the world couldn't be arsed to give a damn about what people are singing and strumming today, at any price!