More convenient yes, MORE secure, no. I agree with C. Burch, you are adding another potential failure point, period.
So, a single threaded attachment that is frequently unscrewed and rescrewed and subjected to torsional stress during use is going to be more
stable than a threaded attachment with threadlocking applied plus a clamping screw that's not subjected to unintentional torsional stress? Sorry, no. Yes, in theory
, two connection points vs. one means two possible failure points rather than one. If you were doing a 350' free rappel (I've done one), would you prefer to hang from a single loosely tied knot, or a pair of 8,000-lb-rated carabiners connected in series? The latter has two
possible failure points vs. just one - it must be less safe, right?
I can tell you that I spent over a year with the single lug connection, first as a FastenR-2 then FastenR-3 connected to a tripod socket, then with a FastenR-T1 connected through a Manfrotto RC2 plate. I would frequently find the FastenR slightly loose - probably at least once per week. It never loosened sufficiently for the camera to fall - but that's because I quickly got in the habit of checking the tightness of the lug several times a day. In over a year with the FastenR-3 Loctite'd to a Kirk clamp attached to a body or lens plate, I have never had anything come even slightly loose. I know which sounds more failure-prone to me, and I'm not a fan of letting untested theory outweigh empirical fact.