I will always cut-back on where the wires were previously terminated. I think it is just good practice to do so.
Regarding the process being "Slower" ...... I suppose it is, but you're talking in the area of additional seconds so it's not a game-changer in that respect.
As regards the benefit to Openreach ?? I'm only guessing here, but the 'Tool-less' design has probably been introduced as a means of eventually saving on the tool budget. With 24,000 engineers requiring 24,000 Krone tools at approximately one a year, that will be a no brainer to a bean-counter !! It's not just NTE's that are going tool-less ...... the street cabinets are as well.