There are downsides with the cheaper boards, in addition to size, such as idle power consumption which is typically hideous. Virtually all of the inexpensive boards are just warmed over (or exact copies of) reference designs. He actually is sweating the details to try to make his board the best version it can be for those wanting a better dev board but not wanting to go as far as designing their own. But sure, if cost dominates everything else, his stuff is more expensive.
Here's my favorite thing I saw with a cheaper board: Lilygo/TTGo makes a number of boards with built in Eink displays. Eink is awesome for many reasons, one of which is that the display only uses power when you're actively changing what it shows.
Should be great for low power applications, right? NOPE! First off, their official docs were totally wrong about what battery connector the board had. Then it turns out that the board has horrible power consumption during sleep, which is only partially mitigated by melting off the always-on power LED.
Adding insult to injury, the voltage regulator on the board is actually one that was intended for portable battery packs. When current draw goes below a certain level for 5 minutes, the voltage regulator just turns off. Any attempt to deep sleep for more than 5 minutes causes the board to commit suicide.
They're not all bad. My current favorite is the Firebeetle from DF Robot. At $6.90 a piece, comes with a JST 2.0 connector for a 3.7v lipo battery and, more importantly, runs using 10 μa in deep sleep easily. (Measured on multiple boards). Finally, is well documented and has great support from the supplier.
