OMG Network is a unique and frequently misunderstood service layer solution with a quite distinctive current use case. The network actually does not use smart contracts and is built for transactions, making the integration of Tether USDT onto the OMG Network a solution around the high fees and congestion currently within the layer 1 Ethereum network.
A similar solution is Optimistic Roll-ups, however the trade-off for scalability is the ability to implement smart contracts for Optimistic Roll-ups. For the simple use of USDT swaps, Plasma seems to have the advantage.
Why is this important?
As we know with conventional gas fees on Ethereum, they have been sky-high and will only get more expensive as the network effects for the Ethereum network progresses.
With the ability for layer 2 solutions to take the load off the Ethereum network, processing transactions or interactions in a more efficient manner, it can free up congestion and make things a lot quicker or cheaper for those wanting to interact with tokens on the network.
If each USDT transaction can be processed much cheaper and quicker on the OMG Network than it would do as a conventional first layer transaction, we can see why exchanges would utilize that instead, saving a lot of money due to their velocity of inflows and outflows of USDT each day, not wasting money on Ethereum gas fees.

We have already had confirmation that Bitfinex has decided on using the OMG Network, with the potential of Huobi and Binance making the move too, as we can see they are aware of the situation. With the cost reduction and speed enhancement, it would be surprising for any digital asset institution to ignore.
Also, exchanges would hold a strategic reserve of the tokens which would take a portion of the supply out of circulation.
What could this mean for OMG Network moving forward?
The market capitalization of USDT is currently at 10 Billion dollars and there are several other notable stablecoins in existence, such as USDC, TUSD and BUSD. We could get a transitional wave of demand from other USD stablecoins onto the OMG Network, switching over from just using Ethereum layer 1.
If the primary nature of Plasma is to solve transactions, it could potentially open up the possibility of other asset-backed stablecoins, as well as forex.
Gold-backed stablecoins are picking up demand, with the ability to hold custodianship over gold-pegged digital assets, which could be a big transition from purely physical holdings or ETFs moving forward.

In countries like Argentina where there is massive inflation but also capital controls, they are implementing limits on residents swapping their currency for foreign currency such as the dollar.
Stablecoins could pick up enormous traction as people flock towards preserving their purchasing power, as governments have been mis-managing the funds, with the trade-off being inflation or even hyper-inflation for their native currencies.
Also looking at how swap-lines work, it is the gateway in which the USD can be used to loan funds to countries or institutions via the central bank. The issue is that there is currently a liquidity crisis, whereby the money cannot get where it needs to be efficiently enough.

Implementing a digital alternative like OMG Network’s Plasma can potentially be a solution to this issue, although there is some competition in this space, such as with the workings of Ripple’s ‘On Demand Liquidity‘.
Looking at the OMG Network roadmap, it states that they have plans such as a decentralized exchange and in future, the ability to implement smart contracts:

How does Plasma work?
Being a layer 2 solution, Plasma is simply a pattern design idea that allows for a snapshot of a transaction to take place (a hash, or known as a merkle root) from the second layer, which is then sent to the root chain (Ethereum). This is compact and allows for funds to be interacted with efficiently.

The More Viable Plasma mechanism is the type of plasma that is used by OMG Network. It is Fungible, therefore consisting of interchangeable units that are the same as each other.
It is a single plasma chain that is optimistic (perceiving transactions are valid by default) and is based on UTXO, the unspent output for a transaction, which is responsible for beginning and ending each transaction.

This makes it much easier and quicker to process a transaction, the inclusion of Exit Priorities is to ensure the security of the network, which is a mechanism that makes sure that all parties (The Operator, Ethereum smart contracts, and Watchers) validate transactions.