About ATTINY85 Development Board I am thinking to buy one of "ATTINY85 Development Board"...

Before buying I was checking details/Advantages of it.


First I thought this is just a breakout board &amp; USB for power.

But, then found It can be programmed with "Digispark driver &amp; board manager" directly by the USB.

 

I checked this Question: EBay “Development Programmer Board for ATtiny”

Someone said there: 


  "While limited, this type of board can be useful for "blink an LED on
  USB command" type tasks"


 
My Main question is:

Is it really programmable withut any TTL/ICSP/FTDI extention?

If so, is it possible to program other AVR chip (Attiny/Atmega) with simple codes directly via USB...?

(with same method)
Is it really programmable withut any TTL/ICSP/FTDI extention?


Only if you use an ATTiny chip that has the "Micronucleus" bootloader already installed.


  If so, is it possible to program other AVR chip (Attiny/Atmega) with simple codes directly via USB...?


Some can, but most need a bootloader installing. The ATMega32U4, for example, has a "DFU" mode, which is essentially a bootloader in ROM, that you can use directly over USB.  In general, though, the answer is "Not without installing an appropriate bootloader with some hardware programmer first".