The Bitcoin Taproot soft fork will optimize scalability, privacy, and smart contract functionality. It will bring about a new address type, allowing bitcoin spending to look similar regardless of whether the sender is making a simple payment, a complex multi-signature transaction, or using the Lightning Network. Moreover, Taproot addresses will allow users to save on transaction fees — the more complex the spending conditions, the more the user will save — compared to previous address types. By reducing the transaction size and making nearly any transaction appear like a simple, single-signature one, Taproot will also enable larger and more complex operations to be deployed on Bitcoin that were previously unfeasible or almost impossible.
This reduction of costs and the increased flexibility and capabilities for smart contracts will ultimately enable very complex setups that were previously not feasible in Bitcoin.
Over the long term, upgrades like Taproot and Lightning might effectively render altcoins redundant and unnecessary. If a given functionality can be implemented in Bitcoin, the most robust and secure network, it is only natural that it will. While altcoins foster innovation and eventually showcase some exciting use cases, they can be more accurately seen as experimentation playgrounds. Once real use cases are found, they will likely be ported to Bitcoin –– their best bet for continued, long-term development and usage.