And if you come back to this script in a few years time and it pulls a newer version of numpy with an incompatible api, there is no easy way of knowing which version it was designed to be used with...
It might be cool if uv ignored dependency versions newer than the script's last modified timestamp, but this behavior would probably need to be very explicit to avoid the situation where a working script is mysteriously broken by making an innocuous change which updates its last modified timestamp, causing uv to resolve a newer, incompatible dependency version.
[0] https://docs.astral.sh/uv/guides/scripts/#locking-dependenci...