The main difference between Bitcoin and Bitcoin Cash lies in their block size limit and transaction speed. Bitcoin has a smaller block size limit of 1MB, which can lead to slower transaction times and higher fees during periods of high network activity. On the other hand, Bitcoin Cash has a larger block size limit of 8MB, allowing for faster transactions and lower fees. Additionally, Bitcoin Cash aims to be more scalable for everyday transactions, while Bitcoin is often seen as a store of value similar to digital gold.