I recently got to BA Gold, which is OW Emerald.
Ok, so I am kindof a newbie at OW but have been Gold on *Alliance for about 6 years.

My own mistake, but I was very surprised that I did not have any extra baggage allowance on CX Y as a top tier card holder on OW. At least at *A I know I have 20kg extra above any class allowance.

Sure BA allowance is great when flying on BA, just found it very surprising this did not get replicated in the alliance.

Globalist

It's one of the downsides of OW that there is no alliance-wide excess baggage benefit. I find that often carriers will look the other way on this, but it's not a rule and they can and do hit you up for extra money. My chief complaint on this is that check-in agents will often inform me of my excess baggage weight like I'm not going to be allowed on the plane unless I chuck a bag. When I ask if I can just pay for the extra allowance I get a response along the lines of "Oh, that's what you want to do?" It's not like there's a choice here.

The excess fee is usually reasonable but can at times be shocking. I was once traveling KIX-SIN on JL with 2 bags at 22kg each. This would have been free on AA as an elite or, as non-elite, ~$40 for both. JL quoted something in the $600s. (Yes, it's because I only have a 20kg limit in Y and full Y fares KIX-SIN are outrageous, and KIX has very high landing fees. Doesn't mitigate the sticker shock).

Being OW Emerald, you will find that OW is the only alliance to give access to First class facilities (check-in, boarding, lounges) as a top tier alliance-wide benefit. If extra baggage is very important to you, then OW isn't for you.