NO doubt when possible managed modes should be used but when unrestricted climb has been given use of OP CLB is what it is for. To stay in CLB by deleting waypoint is creating laborious head down work because you have to ensure you are not deleting a wrong constraint. Climb and descent have a difference. CLB and OP CLB are same without constraints they don't track any vertical path but in descent even without constraints DES follows a path calculated all the way to 1000ft on approach. OP DES is used only when you want max rate of descent with idle thrust. If you deleted constraints in descent FMS will rework the path but nothing of that sort happens in climb.