Why did Apple get rid of the sleep pulsating light?
It was like it was breathing which indicated it was sleep.
Mac Studio (2023)
That is a fair question. Problem is that this is Apple's user to user forum and only Apple has the real answer.
To make matters worse, Automatic Computer Sleep has not worked properly in the latest macOS versions and some folks have had crashing and other issues while the Mac is in computer sleep mode.
With that in mind the best practice is to:
Turn on "Prevent automatic sleeping when display is off"
Then only allow the display to turn off during the day and shut down... for long periods of none use.