Right now to report impressions/clicks aggregated by creative and
keyword we'd need to use AdPerformance report that always aggregates
not only by ad ID, but also by each ad URL, which doesn't make sense.
If I use keyword insertion in the URL this report is useless. Well,
"useless" is an overstatement, but it's very inconvenient if all I
need is ad ID and keyword ID in the report to aggregate stats by. And
I am pretty sure that most large-scale users use IDs in their systems
to synchronize with Google, rather then supplemental information such
as keyword strings and URLs.
Second thought: actually it would not be a problem to have the report
aggregated by adID AND adURL, even with keyword insertion, but the
fact remains that using CustomReportJob was superior because we were
not forced to include into the report information that we don't need.
If I only need adID and keywordID to aggregate the stats by, why does