Double barreled surnames?

Two of my GC have a double barrelled surname, my son and his partner aren’t married and are happy for the children to use one or other name or keep both whatever suits them as they get older.
They live abroad and I know some of their friends have done the same.

Professionally my DiL is Dr X but in her personal life she is Mrs Y. They went that way to avoid the double-barrel.
Their baby will be baby Y.

I personally don't know anyone with a double barrelled name, I think it a tad pretentious, says me, brought up in social housing ( a council house)
However a friend's D married a man with one, it was quite a mouthful, and we were told about it a lot.
After hearing, perhaps once too often, we referred to them as Mr and Mrs Charles Double Barrelled. We heard less after that. I know, I know, that wasn't very nice.
I can't really see how the future generations will handle it.

Always reminds me of the very pretentious woman in Coronation St who decided she would be Battersby-Brown...lol.How hard is it to decide on one name when you marry instead of doing this.It has worked for a long time.After all most of us had our fathers name