The way it integrates into Django is more than just an abstraction to SQL. It's also an abstraction to your table schema, mapped to your model. In short, it's the Pythonic way of fetching data from your models in Django.
It allows for functional programming, as in building queries upon other queries. And predefined filters, easily combining queries, etc. And much more.
Of course you don't need all of that. But in a big project, where you might query some particular tables a lot of the times, and there are common joins you make between tables, then sometimes it is nice to have predefined models and columns and relations, so you need less verbosity when building the queries.
You do of course need to learn a new tool to build queries, but it does pay off in some cases.
It allows for functional programming, as in building queries upon other queries. And predefined filters, easily combining queries, etc. And much more.
Of course you don't need all of that. But in a big project, where you might query some particular tables a lot of the times, and there are common joins you make between tables, then sometimes it is nice to have predefined models and columns and relations, so you need less verbosity when building the queries.
You do of course need to learn a new tool to build queries, but it does pay off in some cases.