Now a specific company A may not agree to interact with a "permissionless" public blockchain such as Ethereum. Instead it prefers to establish it's own "private" blockchain to manage employee management internally. Given various blockchain frameworks (like Stratis etc.) it's rather easy to instantiate private blockchain. Company A also decides to use it's own "currency" or "tokens" for microscopic incentivization schemes. If this differs from the Main Chain (which is Ethereum in this case) currency (Ether), fragmentation can happen as many companies will end-up choosing their own tokens. Increased fragmentation will ultimately affect the liquidity of these reputation tokens and may prove to be an impediment for employees to cash-out a % of those tokens. It will also imply that without an universal reputation token, conversion between various tokens and ether would be a nightmare ! So to keep things simple lets use "Ether" for time being as the currency of all private "sidechains".