Sure, it isn't such a big deal when you're just starting out as most professionals and experienced users recommend the Arduino Uno. However ... Micro's size and male pin headers make it perfect ...

[Andrew] writes in with his Z80 single-board computer made from scratch, using the Arduino standard headers ... digital converter and a 3.3 V regulator, mimicking the pins found in an Arduino Uno.

The Sno (pronounced like “snow”) board is a tiny footprint Arduino board that you ... prototype on the XLR8 which looks like a UNO or you can put headers in the Sno. They also sell a breakout ...