Yeah I get that. I never (or very rarely) buy shoes or clothes online for much the same reason. What you order and what you end up with aren't always one and the same!
I reckon they probably offer discounts to companies bulk-buying from them, but if you're just buying one for yourself then they do seem to come at a premium. The chair I bought online turned out to be far better than any of the ones I saw at ODM, and for about half the price.
I went there last year, they have a decent selection but were ridiculously expensive, mostly £250+ for some pretty bang-average chairs. I ended up going on Amazon and taking a punt on this one
https://www.amazon.co.uk/gp/product/B07L5LVH8S/ref=ppx_yo_dt_b_asin_image_o05_s00?ie=UTF8&th=1
and I...