There is only upside to using foreign keys. When enabled, the benefits are obvious, so I won't discuss, and as for the drawbacks, the only drawback is performance. But if that's a concern, then guess what, on most databases, you can disable foreign keys.

Well, one might ask, what is the point of having foreign keys if they are disabled? And the answer is, there are several benefits. Here are a couple:

1. foreign keys, disabled or not, create a record of your data design that itself serves as documentation, and that can be programmatically queried, extracted, copied, modified etc, all of which reduces technical debt and is useful for other users or developers to understand your schema and work more efficiently.

2. You still have the option to enable the foreign keys. Furthermore, you can pass this job over to someone in your organization who may not have authority to create or modify foreign keys, but does have the authority to enable them and/or to fix the data however required to enable them