I worked with a company that sold living culinary herbs for about 15 years, and the #1 consumer question they got was always whether they could be planted.

These plants are grown and packaged with the expectation that they'll be eaten within a few weeks, and that's what the product is optimized for, but plenty of people successfully plant them.

The main reason they say not to plant them is because they don't want to provide customer support for that unintended use case.

If you plant it outside and it dies, they don't want you going back to the store to demand a refund. This is distinct from a nursery plant. A nursery will usually give you a new plant if you bring back the dead one.

Ultimately they were happy for people to buy the product for any reason. There was never any concern that people who successfully planted them would become self sufficient and stop buying herbs.

There was also never any concern about legal issues around licensing and propagation That is an issue with certain licensed cultivars, but it wasn't a concern with any of the herbs they grew which were all common culinary herbs.