Absolutely - it's their money to spend as they see fit and if they've done their homework and gone it eyes-open as to what to expect, fair play IMO.That's something I also have noticed. Most people I know who changed their groupsets to ultegra or dura ace...they just did it because they could afford it. Benefits of those groupsets over what they had? Largely intangible, according to them.
Still, all the changes they made, they made because they make them happy. Which is fair play
End of the day I think most on here have an appreciation for mechanical items and if you have the money it's nice to have examples of nicely-engineered products just to appreciate their intrinsic qualities.
The people I struggle to deal with are those who suck up all the marketing dross and buy high-end gear because they think it makes them look superior than everyone else
Unfortunately for me I'm not blessed with enormous amounts of disposible income so all my bike-related decisions are made firmly on the basis of value and as such I find myself at the low-mid price-points.. if it gives 80% the performance for 50% the cost, I'm in!
All that said I don't feel the need for displays of conspicuous consumption and tend not to concern myself with stuff I can't afford / gear that would yield little intrinsic benefit over what I have, so in this regard I'm fairly content with my best-bang-for-buck gear