I'm really happy with this trend too. Your post made me think about what retailers have to do to represent their clothes without letting us handle them or try them on. Multiple angles, multiple models, suggested combinations with other items, measurements, fiber contents . . . It's a lot compared to steaming a top and putting it on a hanger.
Back to your point - I always flip through to see if there is an image in a model closer to my size. Several retailers give the measurements and height and sizes of the two models. I particularly appreciate the height information, as I can then guess where the sweater or jacket will actually hit me.
The Gap does this really well (https://www.gap.com/browse/pro.....X2JwRVRGcz)
I also thought about which brands will probably NEVER do this. Boden, despite its recent groveling and its good range of sizes, will likely never show a plus size model, although they are pretty good about showing a range of ages. They also encourage customers to post selfies, which means you occasionally see a larger (or shorter) woman.
Remember when you had to pay more if you were over a size 14? That made me grind my teeth.