While I definitely author fewer classes in F# compared to C#, I do still use classes a bit. The main advantages for classes I see offhand are:

Sometimes an object with mutable state and an encapsulated abstraction just feels like the best way to model something, in which case classes are a great fit.

Members are often more discoverable than let-bound functions in modules, thanks to Intellisense and 'dotting into' objects. (Admittedly you can put members on DUs and record types as well as on classes.)

If you want to create a library API that is usable from other languages (like C#), the namespaces and classes are definitely the right way to expose a familiar and interoperable API.

Classes do interfaces and inheritance. Though I use these more rarely from F#, it is still good to have them when you need them.

But different people may have different opinions on this topic.

I'm interested in build an AI system, it's about knowledge.

There's a base class names Descriptor with properties Name and Description, and now I want to make a derived class names Machine with a new property Parts. Is there another way in F# makes equivalent result?

I searched about "inherit" in the reference and it says only classes can be inherited.