All this and... the only reason to grab in the first place is because you're planning to push or pull. And in Aikido, both are wrong.
I disagree, unless we are discussing two different concepts of "grabbing."
The baseline way to apply nikkyo or sankyo or kotegaishe is to grasp uke's hand to secure it.
And people with bad arthritis need to find an alternate way to compensate for weak or painful grasp.
There are times to do standard nikkyo as nage hurts me way more than receiving it as uke