Why are there transaction fees?

The design of the blockchain allows transactions to be secure, avoiding double spending of cryptocurrencies (which is essentially an unauthorized chargeback). To do this, the network verifies that all the transaction data is correct before writing it forever to the blockchain.

This is done by the miners, who expend processing/compute power and electricity in the process. Transaction fees are the small "fee" paid to miners for the service of confirming your transactions on the ledger.

The fees do not vary based on the amount of an asset sent, and they allow the transaction to be processed more or less, quickly. Although, their value sometimes increases, the fees are often low compared to traditional payment processing services like PayPal.

Learn more about what transaction fees are here