What an unnecessarily combative response. The person never claimed that this service has no value; that’s a strawman you constructed. They’re just helpfully pointing out another (free!) way of accomplishing the same thing for those who might want it.

I assume ($10B) is the current Dropbox, Inc. valuation. Is it somehow relevant here?

Yes, that a company with $10B valuation must necessarily have somehow found a market.

It's a reference to an infamous HN comment about how DropBox is trivially replaceable by an invocation of rsync and thus has no market value.

Yes, but the reference is irrelevant because the OP of this thread never said anything about this service having no market value.

Doesn't this show the complete opposite of what you intended?

Removing attachments is a standard feature of just about any email client, even extremely barebones/cli ones. That was the point. Yet, Gmail is lacks this convenience. Are you seriously arguing that none wants Gmail?

and IT professionals don't use Dropbox for non-trivial use cases. but you wouldn't know that