Sounds like the cons, outweigh the benefits. Especially on the cost side.
When i was young 16 year old apprentice Electrician I use to get a clip round the ear everytime i called them bulbs,
"bulbs grow in the ground nipper there lamps not bulbs"
Old habits die hard i,m afraid
I never got pulled for them and passed 2 mots while i had them on!!
It has been commented that xenons make the non-illuminted areas seem even darker simply because they are so bright and the cut-off so sharp.