LRC is required to function on any exchange or dEX built on Loopring protocol or LRC services. It's kind of like how BTC has gained its status as the price standard for crypto remittance because anyone who uses btc remittance can be sure they're getting their money back even if they become anonymous after sending their payment. LRC works similarly except that it acts as a base value used to fuel order settlement instead of being burned or "destroyed". If more orders are placed at an exchange using that dEx's pair then there isn't enough LRC to get into a ring to match all orders, then LRC is "burned" and destroyed until there's enough supply.
Now back to the infinite wallet address thing. So let's say you have 100 tokens in your exchange account. You want to send 30 of them but don't want to lose what surplus you have in your wallet so instead you signal a transaction that contains both or multiple token addresses in it. The dEX would combine these addresses by doing the same process with each address pair including yours, thus making an accumulation/distribution type data structure which is called a Ring. It combines everyone's order together and does some magic math voodoo which comes out with an answer on who receives what amount of tokens. This process is done every time there's a ring on the dEX, which can be several times per second resulting in instant settlement on trades even if they're cross chain swaps between different blockchain technologies like ETH/BTC.
LRC has another role as well. It verifies order authenticity and integrity by collecting signatures of everyone who put something into the ring to signal transaction intent. If an order doesn't have that verification then it can't go into any ring or fulfill any orders on exchanges built with Loopring Protocol. Hence why you must hold LRC to use LRC services, so do the research before asking questions about "no fees" Honestly though all I've quoted from their white paper was the tech and the rest is just marketing talk so I won't try to translate that. But don't let it scare you if you're new to crypto, read up on technical terms and come back with your questions!
Okay now how about some numbers? As of writing this article Aug 7th 2017 LRC sits at 0.06 USD/LRC. The total supply currently sits at 572,552,412 LRC with a circulating supply of 444,752,412 LRC which means only 20% are available for purchase on exchanges right now.(a little ICO jargon here) According to the officialLoopring website they've already raised 7529 BTC(approx 13 Million USD) during their-ICO round in July 12th 2017. This was oversubscribed the crowdsale cap of 4503 BTC and reached a Hard Cap level of 7930 BTC(approx 11 Million USD) within 66 seconds!
