Can someone tell me a little bit about the background on how piston AR15 became a thing?

Im specifically thinking about the 416. I have read a lot of different reasonings. Some say DI SBRs at the time of 416 invention were not very reliable and thats why some units saw a need for a piston gun. Others say it was because piston guns run much better when using a suppressor. Can someone clear this up for me?

What specifically is it that makes piston guns run better with suppressors should that statement be true?

If at the time of 416 fielding DI SBR in fact were less reliable then what has since changed in DI SBR configuration? What specifically makes a piston gun better when run with a short barrel?