Both Airbus and Boeing have climb and descent modes that will ignore pre-programmed altitude constraints : Open climb/descent or Level change*. (I don’t know about other types).
So why bother to remove them ? As others have said; making unnecessary changes to programming carries a significant TEM risk, and while most of us are perfectly capable of changing constraints - be they speeds or altitudes - one day you might accidentally remove a rather vital waypoint instead.
There seems little point if the system can be ‘told’ to ignore altitude constraints. Better to use those extra few brain cells to concentrate on SA and busy traffic than go heads down. If a descent constraint is irrelevant on the day, and would schedule a descent too early or too late, then, OK, delete it, but otherwise probably safer to leave it alone.
After all, unintentionally levelling at a published SID/STAR constraint that ATC have cancelled is arguably safer than accidentally removing a complete waypoint?
*After years on the Airbus, am brand new to the Boeing, so please correct me if I am wrong.