I used battery grips starting with my first DSLR (a T1i/500D), then the 7D and 5DII. After using the 1D X, I won't go back – the integrated grip is much more comfortable to hold. I travel with the R8 for the smaller size, and because during travel I'm not walking around holding the camera, it's in messenger-type bag or backpack and comes out to take a few shots then goes back in the bag. The reason I like the integrated grip is that with that and the hand strap attached, I can handhold the camera for several hours even with a heavy lens like the 28-70/2. (I was annoyed that Canon dropped the lower hand strap lug from the R3, but it's not a big deal since the RRS plate replicates the strap attachment).
Makes sense. I don't travel with a 70-200mm at all. I have found that for most destinations I don't need longer than the 24-105 (I bring the f/4L version for travel, not the f/2.8). My travel kit is mainly built around the wide end (10-20/4 or 14-35/4, TS-E 17 and/or 24, maybe a fast prime like the 24/1.8 for interiors, and the 28/2.8 (because it's so tiny and works great for street if I do want to let the R8 dangle from a wrist strap). If I'm going somewhere that I'll need longer than 105mm, 200mm won't be enough either and I'll bring either the 100-500L or the RF 100-400 (which is light and punches well above it's weight for IQ).