The Chainlink network underlies many of the most popular decentralized finance (DeFi) protocols including Aave, Compound, and others. This means that the LINK token has a real use case that is being proven out every day.
LINK is included as one of the few altcoins in the Grayscale investor trust, which signals confidence in the token from Wall Street. However, there is no way to know if LINK will be a good investment long term.