I have some "gold plated" RCA connectors that "gold" is not even providing 100% coverage. It's so thin that it looks like patch work.
Less than a microinch gold is considered "gold flash", which is mainly for looks. It does have some benefit against corrosion during shelf storage, very similar to ENIG plating on circuit boards. It is not intended to survive mating; for that, you need 15 to 30 microinches of hard gold (gold with nickel or cobalt impurities).
Not trying to be argumentative here at all, but just thought I'd give you some insight on what we supply on our connector range, for comparison.
- Our "Industry standard" products are either hard acid gold flash (around that 1 micro-inch level) over nickel, or tin (40-80 microinches) over nickel. Even though the gold is pretty thin, it is still a superior coating to the tin for wear (look up tin fretting) - such that gold flash connectors are often rated for as many as 300 operations, whilst tin only for 50.
- Our "High-Reliability" products are generally hard acid gold plated (again over nickel) with about 10 to 12 microinches - more than enough for 500 operations on one range, 1000 operations on another range.
- The use of 15 to 30 microinches gold is OK for the contact area (but can get expensive with little improvement in performance), but definitely not recommended on the solder tails - the effect of gold embrittlement kicks in, where gold molecules mix with and weaken the solder joint over time.
All the contacts are copper alloys - brass, phosphor bronze or beryllium copper - giving different levels of spring force and long-term performance, and will be used as appropriate depending on the rest of the specifications.
Generally our connectors are used for in-equipment connections, and to be fair many seem to end up in the fit-and-forget types of applications. But the thinner platings with gold are still perfectly good for function. However, the standard of the manufacturer is key - to ensure that you have connectors with good plating adhesion that will not flake off, as other members have encountered.