Explain Like I'm Five

Just bought Galaxy XCover 6pro. Lost many features I had in my previous phone. Kept removable battery and headphone jack. Gained notification led.

Can't say I really missed it tho. I'd trade it for an optical image stabilizer.

The nothing phone has led glyph indicators on the back.

Why did LED notification lights silently got removed from phone?

What's the normal sound of removing feature from the phone?

On more serious note, this is why I have smart watch.

When you have questions like this, the answer is almost always money.

For this particular question, it is money - the cost of the LEDs (which is of course minimal, but multiplied by millions of phones), but also manufacturing (need to have a hole in the case to let the LED shine though which can let water ingress into phone). To make those holes water tight would add more cost so instead they decided to use the screen itself as the notification method. I think Motorola's implementation of this was the best - they had their always on display to show notifications and a single tap would let you see what the message was even if the phone was locked.

My phone still has the LED but I turned off the feature long ago including the battery low and charge indicators. More annoying than useful.