I used one to control a pair of candy machines for a Watson demo - there was a laptop with a microphone that did sentiment analysis on your speech, and then it told the Arduinos to give you either sweet or sour candy.
The next version is probably going to have a Raspberry Pi replace both the laptop and the Arduinos, but they were a good starting point to get the project up and running.
RaspPis are startlingly cheap these days, and surprisingly capable.
For less than a tank of gas, I just built a retro ROM console, and the new version 3 boards are beefy enough to run video through Kodi without missing a beat or play any old console games I've tried up through the PS1/N64 era.
They're not really equivalent. The Pi is a full-blown computer, for better and for worse. The Pi Zero draws 70mA at idle, while the Pi 3B draws more like 300mA even with most of the peripherals turned off. With a bit of tweaking, an Arduino will run for months on a coin cell.
That is not true to all countries and regions. For example, in Brazil a raspberry pi 3 will cost a bit more than USD 100 which is a lot of money for many people and prevent it from being acquired by low and middle income classes which are arguably among the ones that would most benefit from access to this ecosystem.
Arduino/Genuinos on the other hand are easily available on our version of eBay and can be purchased as low as USD 30 which is an order of magnitude difference between the prices, and yes, one is a real computer and the other a microcontroller but sometimes you get what you can afford.
this schism between arduino people is completely ignored here and we'll buy the cheapest chinese knockoff if it is available.
Yikes! Is that because the main distributors (RS/Allied Electronics/Newark) charge more to ship it to Brazil, or do they just not ship there at all and make you purchase through more expensive re-sellers? (Or is it something else like tariffs?)
Case one: $35 (product cost) + $40 (international UPS shipping) + $100 (import and administration taxes)
Case two: "I bought one R-Pi from Farnell Brazil (http://www.farnell.com.br/) and I paid R$185,50 ( ~ U$90) with taxes and postage."
I remember trying to help some Brazilian users find the cheapest way to get a hold of one a couple of years ago, and I heard similar stories: high import taxes even when there were official distributors operating in the country, and high shipping charges when there weren't and they needed to order the devices internationally. I don't think that it's resellers trying to fleece their customers. I think it's just a fact of the Brazilian government's policies.
Of the main Pi distributors, only Newark had local operations, and they closed shop last year.
Now the cost is higher due to low volume imports, so you end up paying more for shipping the boards. Also, taxes are higher if an individual is importing stuff, as customs use a simplified 60% tax over the retail price vs using the specific import tax (around 45% for the Pi) over the reseller price.
Taxes and greediness play a strong role in Brazil. For example, I just imported 10 Tessels to start a class on IoT. So they charged 98% taxes, (60% import taxes + 20% icms + 18% of administrative fee from UPS).
Not an endorsement of this, but nothing that I have order directly from China has ever had an honest customs declaration on it. It's always a "gift" of "soap" or "lotion". I'm guessing if you charge 98% in taxes it's worth it to have customs agents who actually inspect things though.
The next version is probably going to have a Raspberry Pi replace both the laptop and the Arduinos, but they were a good starting point to get the project up and running.