Yes and no.
I see your point and accept it and it is true under some conditions. But I don't fully agree with it.
Let me explain.
If you are on say a dry lane that is fairly tame. Then yes they are fine. But venture more into the wilds and there are two issues:
1. Much higher risk of puncture.
2. The simply won't be any good if it really gets muddy. M&S might claim to be mud rated, but tbh it's a bit of a cop out. And you can very easily end up getting stuck or sliding about all over the show, where the same vehicle on better tyres would have no problem at all.
You see and here of these things all the time. Many a tread is posted where people have got stuck, or slid into something and I've seen it first hand many many times.
E.g.
Terrain like this and road tyres like you posted, you are at far greater risk of punctures.
And you'd find traction lacking on terrain like this:
If you are only driving on lanes like this, in dry conditions, then I do agree. Those tyres would be fine. But you'd need to know the lane to know that it wouldn't get worse.
And arguably wet grass is the worst thing for traction.
This lane was mostly grass, but it started from a small Welsh hill farms yard and went straight up a very steep slope, At least a 1 in 3, but probably slightly steeper. A small amount of rain would make it very challenging to ascend on off road tyres, let alone anything else. And of course, you could end up having to come down it and the lack of low range on the FL would probably mean brown trouser time, or an accident. Indeed the farmer told us someone in a Disco had come down the slope last year and taken out part of his wall.
My advice to the op would be:
-If you are having one set of rims. Then make sure you run a good AT tyre on the more aggressive end. They might not be the best on road, but they should be fine. But they will make up for it when needed on lanes and off the beaten path.
-If you are having two sets of rims. Then get one set of MTs and the other road biased. That way you'll be covered. But it will mean you'll have to change tyres before venturing out.
-If it was me, then I'd probably opt for a MT and just run it daily. But that's me and I accept it wouldn't suit for everyone. Although to some extent it will depend how many road miles you.
I can't recall the size of these, but slight bigger than standard for an FL. No rubbing, stock suspension. They are actually a remould copy of the BFG AT, think they might have been Insa Turbo of some kind. They wouldn't be my first choice of tread pattern, but we had a set lying about hardly used and needed tyres on the FL.
It ran perfectly on them. No issues at all on the road.