Yes, I think that would be a useful option, or perhaps phrasing like “Allow notes to obscure the half-bar division in 6/8 when all notes in the bar are greater than the denominator.” That would allow half-quarter and quarter-half too which are common as well. Once eighths are introduced anywhere in the bar, then it’s back to standard beaming.
I completely agree this setting should not be the default, and honestly I’ve never had an issue with just using Force Duration, but notating 3 quarters and half-quarter in 6/8 is very common in 6/8 Afro-Cuban music (look at virtually any bass part), and other styles including some Argentine music, and is the standard notation a performer expects to see in those genres.
The Villa-Lobos Prelude #1 is another good example of 6/8 and 3/4 existing concurrently, although I’m not sure how any beaming setting would help here other than just using Force Duration:
A bit OT, but here’s a wonderful arrangement of that Prelude #1 for bass and string quartet by new Dorico user Pablo Aslan. He’s been posting on the Dorico FB page and I assume lurking here …