It is neat for people that find that tooltip apparition delay is too smal or too big. As discussed here : https://discuss.kde.org/t/all-this-time-i-just-thought-it-was-slow/30523 . The setting already exist but have no GUI for it.
If we added a GUI for this, people would assume it affected every tooltip across the system (which would be a logical assumption), but it doesn't, which means we would need to phrase it in a very special way to communicate that it only affects *certain* Plasma tooltips. This is the kind of UI that can't help but either be a broken promise, or end up incoherent and contributing to the sense that "KDE is overwhelming". Instead we should remove that hidden setting, use the standard Kirigami tooltip delay value, and tweak that if needed.