> When I'm doing design work, there is a product spec already defined but it almost always changes once initial designs are completed and people have a better understanding of how it would work in practice.

In my case, I am just iterating on the fly with our end-user(s) (we also do not really have a product owner).

It may not have been obvious, but I am working on an app for internal stakeholders, not for external customers (the customers that my company serves).

So when it comes to designing for external end user + customers, design is serious and necessary consideration, which is where Figma would come in.