When should one send a PR and when not?

[Ottavio Caruso <ottavio2006-usenet2012%yahoo.com@localhost>]

I have a few packages that fail building or configuring on Debian 
Stretch (why I still use an obsolete Linux distro is a long story). I've 
given a casual look at pkgsrc-bulk@ and I've noticed that these packages 
also fail on non-NetBSD bulk builds with similar errors.
I'm not a "quick fire PR" kind of guy, so I asked on IRC if it was worth 
sending a PR for these packages. The reply I got was (recalling from 
memory and paraphrasing): "if the package already shows up as failed in 
the bulk build logs AND you're not providing a patch, there's not much 
point submitting a PR".
I totally get this point and I totally get that non-NetBSD builds may 
have a lower priority and I surely don't want to make the developers' 
lives harder than it is.
However, I did, in the recent past, submit PRs, without offering 
patches, for packages that were known to fail and, in most cases, this 
led to a quick and positive resolution of the issue.
I'd like to hear your brutal and honest opinion on this topic.

In any case, would it be worth adding a reminder that one should also 
look at the public build logs before submitting a PR?
--
Ottavio Caruso