I don't think its a problem as you mentioned, but its a best practice to lock the compiler version to the one used to test your contract to avoid any kind of issue that might be introduced in the new versions. Lets say a new compiler version introduce a vulnerability, that might affect your contract as well. Unless you're developing a contract that will be consumed by other developers, its recommended to lock the compiler version as specified in the consensys best practices.
Contracts should be deployed with the same compiler version and flags
that they have been tested the most with. Locking the pragma helps
ensure that contracts do not accidentally get deployed using, for
example, the latest compiler which may have higher risks of
undiscovered bugs. Contracts may also be deployed by others and the
pragma indicates the compiler version intended by the original
other security tools can help also discover vulnerabilities during the development