Miners collect Bitcoin (BTC) transactions into distinct packets of data called blocks. Each block is cryptographically linked to the preceding block, forming a "blockchain."
The size of these blocks is currently restricted to below the average daily demand, making transaction fees for Bitcoin (BTC) a competitive marketplace. Since miners earn the fees from transactions included in their blocks, they have a direct incentive to mine larger blocks with more transactions. As more people use the Bitcoin (BTC) network for Bitcoin (BTC) transactions, the block size increases.