Add A Table For Values That Will Never Change?

What the right table setup is when you have a table with values that will never change.

I'm building a small project for our sales team so they can track their leads & customers. I have a table called "Contacts", which contains the names of every prospect they've ever reached out to. In that table is a field called "ContactTypeId", which is a reference to a table called "ContactTypes".

My ContactTypes table looks like this:

ContactTypeId | Name | Description
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1 | Lead | A contact who has shown interest in our service
2 | Qualified Lead | A more deeply engaged, sales-ready contact
3 | Customer | A contact paying for our services

So, I set it up this way because I figured it was cleaner to associate a ContactTypeID# to each Contact in the Contacts table, rather than actually spelling out "Lead", "Customer", etc for each record in the Contacts table.

But is this right? If these values in my ContactTypes table are NEVER going to change, should I still have this table at all or is it better to just insert "Lead", "Qualified Lead", or "Customer" into the Contacts table? Just looking to take the correct approach.