The article talks about both tx fees and private fees you pay when you buy sell coins on an exchange.
To send the $25 from the United States, Nuzzi used a credit card to buy an equivalent amount of bitcoin on exchange Coinbase Inc., which charged a 3.99 percent fee this month. Then he paid a bitcoin network fee of $1.34 to send the payment to the U.K.
While converting bitcoin to pounds was free on the exchange Coinfloor, Nuzzi had to pay $13.56 to place the money in a U.K. bank account. He ended up paying $15.90 to get the payment through.
The example is a bit extreme but it does show one thing.
For small amount and if you need fiat at the end of the process, bitcoin is not the cheapest options.
When you send large amount over 1k, it starts to look far better.
I dont fully understand the dynamics of what drives the transaction price either, to my understanding (which may be flawed) the transaction cost is adjusted to incentivize miners to process the transaction into the next block.
Users compte for the space in the next block. Higher fees go faster cheaper tx might never get a spot.
Pretty simple.
More transactions, higher demand for space, higher fees.