I think you and GM recommended that it become a written out ability.
I think we probably said that because of the Limit inclusion. Generally keywords should not be within other keywords. It’s confusing, easy to forget, and leads to looking up chains of abilities just to see what “one” ability does.
I should have mentioned this when I posted the Tesoro – I am using a custom version of your Hidden Gold ability without the Limit keyword. I’m sorry if that’s against your intent with the keyword, but I think it remains a fair ability (not super OP even at a relatively low cost of perhaps 3) and becomes both less confusing and easier to use than it is with Limit attached. Similar to what Woelf has said, I maintain my stance that adding Limit to things is not a good way to reduce their cost or make them less OP. I really like the keyword so I hope you don’t have a problem with me using a modified version of it.