I 100% agree here.
Overlapping the stays onto the ends of the TT miter means that the stays are welded/brazed to a thinner tube than it would be if welding or brazing straight to the seat tube since the walls of the ST will likely be thicker than the TT.
I’d personally prefer to do it the other way around - tuck the ends of the seatstay miters in under the “ears” of the TT miter. That’s if you insist on any overlap at all.
For the same reason I do not like seat tubes that are so pushed forward that they mostly or wholly join onto the down tube (not a BMX thing, but some MTB’s get made that way). Have no real data or anecdote that it’s bad. It just gives me that feeling it’s less than ideal.
[Edit: My post in the BMX appreciation thread shows how I did it on the two fillet brazed BMX frames I’ve built. Stays tucked as close to the TT miter as possible without actually overlapping.]