Because Adafruit makes it easy to find and usually has some amount of tutorial/howto easily findable from the product pages. Not everyone knows that these parts can be sourced more cheaply; not everyone cares. Plus, there's some higher assurance that you're going to get what you pay for from Adafruit.

For that matter, why buy from Ebay when you can often get them cheaper from Aliexpress? (Or even cheaper from Taobao in a lot of cases. For me, Taobao is too hard to access as a native English speaker, so Aliexpress is where most of my cheap components come from.)

When you need one, fast, and want it to work, get it from Adafruit and you will be sure.

When you need 10, then its time to look at ebay.

Also, Limor is a force of nature. You know how to use half of that random chinese stuff you find on ebay because Adafruit or Sparkfun went there first and left libraries in their wake.

Because they write a lot of software and tutorials on multiple platforms for the devices they sell and people are willing to pay a little more to support them.

I buy stuff from Adafruit because they do good work. They are advocates for approachable and understandable electronics. They work hard at combining art and technology and education. They pick good components and they make software libraries and tutorials to match.

I buy their stuff because I think beginners should buy their stuff and I want to see more companies like them exist.

It's more about getting what you pay for rather than relying on your expertise to get something working. Plus Adafruit writes good software and tutorials to get you up and running.

When you are going in for a hobby project, you tend to go towards a more 'established' and 'complete' solution including software than having to rely solely on your expertise.

Sometimes you can't source stuff from A/X, especially for more special purpose parts. I've never been able to find for example the MCP9808 on A/X for cheaper than the Adafruit price, though you still have to pay shipping (but you get it sooner in compensation). I also think the Trinket Pro is a reasonably priced Pro Mini clone, especially because a lot of the super cheap clones have awful voltage regulators on them. That doesn't matter in a lot of cases, but sometimes I need it.

I agree that a lot of stuff is pretty overpriced, but they are selling premium quality on a lot of their stuff, plus reliable supply chain and lots of support.

I sometimes buy from them because it guarantees a quality minimum. They have a good reputation to uphold and will make sure I'm satisfied in case of any issue. Buying electronics from ebay has a higher risk of receiving bad parts. Which means the project is set back and my time is lost. Id rather pay more and save time/headaches.

Because the eBay stuff is usually a copycat of Limor's work.

Do you tribute the artist or the guy selling the artist's bootleg CDs in the alley?