Professional metal stitching / Framebuilding Appreciation

I am/have been working on something similar to that seat tube lug.
In my case it is to create a better transition from an ovalised Max or custom 31.8mm top tube (measures more like 35-37mm at the junction) to a 29.8mm seat tube. I think Donohue might have had similar idea with their design.

This is the challenge:

You want a steel cross bike to have flat top tube for shouldering but a skinny seat tube for 27.2 seat post.
By having a Max inspired lug you can silver solder this bit and TIG the rest. As opposed to having to braze and file everything. What you sacrifice is custom angle between seat tube and top tube. But for batch production and standard geometry it probably works fine. Or if you can have it custom 3D printed every time.
I am not a fan of the triangulated webbing although I can see it work from a marketing perspective.
I will make my design fit a wishbone (because of other fabrication considerations) instead of the CAAD10 inspired seat stay to top tube transition, although it does look lovely.