I can think of cases where I’d find it handy, but I’m not sure it’s a significant enough need to justify a purchase.
Dorian Tool Bridgeport MMRAA-R8 Right Angle Milling Attachment
He wants $750, but I expect it’s his starting point.
There is value in it. There certainly has been times where I needed an attachment like that. We did used to have one but it appeared to go on a walk about. We looked all over for it to no avail. The one we had was in a wooden case, this was in probably 2018 or so.
That’s about half retail of a new one, maybe 100-150$ off normal priced used ones.
There was one in that auction last month that would have been worth it.