This is not a dig - simply a lead on from your post.
Depends on the roads. Here they would classified as US style Tourers. Big Heavy Straight line comfort. Excellent on wide open wide surfaced US roads - Excellent generally in slowish (but flowing) traffic too. I've not ridden a new Indian or 1800 Wing - but I have a clear idea of what US type wheelbase and chassis shapes do and do not. And what weight is.
And here is why I believe many riders (may be a European thing) on a Longer Tour have moved to lighter multi purpose rides - because the roads left to see and explore (and free of traffic) may well not be 100%. I did my month long tours of the Alps (in the 80's) on the old Guzzi I still have. Often on really poor roads (Cobble stones over tree roots). It was modified to suit the trips - and oddly the riding position is close to a modern Adventure bike. It does not have the ground clearance - and aesthetically very different. But you can for example stand up on the pegs for rough sections with no difficulty. This is simply NOT possible on a foot-forward riding position or a full sport position either.
My issue with 90% of modern "Adventure" bikes for long trips is that I'd need 2" platform soles to cope with the seat height. Tippy toes is fine on a good surface - not so good on mud, dirt or uneven surface. In fact the only "Adventure Bike" I have ridden that I can flatfoot is the RE-Himalayan. It's 24bhp however is NOT really apt for faster highways.
There are sections of road here near me I will NEVER venture down again on anything big, cumbersome and heavy. Some where the R3 sump will ground if you attempt to do a u-turn.
A GT has never been a vehicle for trundling. It is basically a SPORTS chassis/engine that can also do distance FAST with some comfort. And one would naturally forward one's requirements onto one's hotel (with one's servants?) in advance or travel light. The R3-GT reminds me a bit of an E-Type 2+2 (half of one - so a 1+1) - The +1 will NOT travel in much comfort. Neither did the +2 in an E-Type. This is still the case for most REAL GT's. The 2+2 E-Type was a bit to long for tight curves too imo. Whereas the simple 2 seater was excellent.
One of the most inspiring real touring things I have seen recently. Ferry from UK to Spain. A couple off on a 6 month tour of Europe. Both in their 70's (almost 80's) - Both on matching mid sized maxi-scooters. (I don't remember if they were the sort with two front wheels) They'd both just ridden 8 hours from Scotland to Plymouth stopping only for fuel. I saw their itinerary - would put many long distance truckers in their place. They were so relaxed and refreshed the old lady was making up sandwiches from the under-seat cavern and cheering up some Scottish lads on "distance bikes" who'd arrived shattered.
