"TLDR: How does this benefit OHM?" - it means people can swap any crypto listed on THORChain for OHM which makes it easier for people to get access to it. THORChain currently supports BTC, ETH (+ERC20), LTC, BNB, BCH with plans for 10-15 more chains over the next year.
There's a whole market of retail investors who (rightly or wrongly) are scared away from dealing with ETH because of gas fees. Anything that opens up more access to OHM is a good thing in my eyes.
The vision for THORChain is that it will become one of the main decentralised cross-chain exchanges. Other services are starting to integrate Thorchain on their back-end - ShapeShift currently uses it for swaps, TrustWallet is working on an integration as well and more will no doubt follow. So getting a pool on THORChain also opens up the possibility to be included in those services by extension.
As you can probably tell, big THORChain fan, let's get this done!