I've spent years working with TTL so 5V is just more convenient. Besides USB is 5VDC as well. When breadboarding, more than once I've mixed up 3.3V and 5V doma

I've spent years working with TTL so 5V is just more convenient. Besides USB is 5VDC as well. When breadboarding, more than once I've mixed up 3.3V and 5V domains with dire consequences - always on the 3.3V side. Unless I really need WiFi, I prefer to go with ATmega. Once you get used to writing structured assembly language, you can get so much more functionality fit within flash memory.