If the envelope is the right size it absolutely does meet all the requirements. Put it in a bubble wrap envelope and it won't stick out.

>And even if it did, once again, it would still be more expensive.

You keep saying this, but so far have not identified what the comparable option you're showing that's cheaper.

In my initial comment I asked for locations, dimensions, and weight. You only provided weight, so I had to guess the others based on the product page.