Semver is important for knowing whether or not to evaluate for breakages. You can theoretically combine both of these by making the date the patch version or supplying it as a version metadata
It can be very useful for continuous improvement and handling forward compatibility. Here's how Stripe do it:https://stripe.com/en-fr/blog/api-versioning, we found that very convenient.
The trade off is that AWS has some godawful APIs (DynamoDB has the least intuitive API I have ever worked with). But they’re stable.
If you go with a date-based approach and create a process + contract whereby you guarantee API stability and / or deprecation date, the developer always knows exactly how much time they have before an upgrade.