A SWOT Analysis can be applied to Companies, Business Units and also to a single product.
It is very common in Marketing and corporate strategy building. And it adds a lot of value when you think strategically about your product.
It gives you a different angle and some thought starters to dive deeper. And it guides you to ask the right questions when you want to focus on product strategy.
It forces you to do an honest review of your project.
It is part of the Product Manager's tool belt. Even if you think "this is corporate stuff". It is useful if you apply it for your context.
I like it because it makes me feel uncomfortable when I think about weaknesses and threats for my product.