Gestures on Macs are irreplaceable for me.

Pretty much infinite options for gestures is amazing.

Yeah, the T-Series keyboards are even better than the X1 Carbon keyboard, and they are a field-replacable unit, and easy to source and replace if they fail or have issues.

Might you mean the "nipple"?

There are many names for it, and not all of them are based on body parts. Wikipedia seems to have settled on "Pointing stick".