Puff pastry is also usually not the main part of whatever you're making but rather just something to hold it together. I see it more as buying pasta to go along

Puff pastry is also usually not the main part of whatever you're making but rather just something to hold it together. I see it more as buying pasta to go along my self-made stew - sure I could make it myself but for most dishes I wouldn't notice the difference. The cake mix is much more defining of the taste of the resulting cake so I'd want to have a say as to what goes into it instead of just using someone else's design.