I would not buy a BD bicycle. There have been many issues documented here in bf with broken and switched parts, improper assembly and issues of moral turpitude*
Habs. are built to a low price point. They are a simple and low cost frame.
If you want "sexy" or a name brand and you have limited funds then I'd be looking at getting a new Lynsky, or a used Moots, Litespeed, Merlin etc.
When you speak of butting you have to also know which tubes are butted and by how much. In a titanium frame if your main tubes are butted and the wall thickness is 0.9mm at the butts and the center is 0.7mm there wont be much weight savings to speak of if that was the intent. The seat tube should be butted near the top where the seat post goes in. Butted main tubes are easier to dent. This is a disadvantage of butting main tubes.
*Moral turpitude is a legal concept in the
United States that refers to "conduct that is considered contrary to community standards of justice, honesty or good morals."--wiki