Principles are different
The basic principles about two FF benefits differ greatly between the USA and Europe. In the USA, the main FF benefit is automatic free upgrades on domestic flights, if avaialble. In Europe, the main benefit is lounge access when flying economy, and (for example with BA) access to first class lounges from certain tier levels, when flying business or economy.
The difference in principles causes some obvious issues for the various airlines in alliances. Top-fliers from the USA may expect free upgrades with the European alliance partners. Top-tier Europeans may expect lounge access. (For example, Continental does not have a lounge arrangement in San Diego, as I found out recently. They seemed surprised that I asked.)
As for lounge access on intercontinental flights, I don't know whether I have got it via my elite tier or by the Business tickets. I will find out next week in Newark. Last time I was still Elite Plus (=Gold) with Air France, but am now Silver, which does not give lounge access with Air France/KLM. I have a Continental "Business First" ticket, and don't know whether that will give me lounge access in Newark.
Momo