Within a Sponsored Products campaign, ad groups are largely unnecessary and can mostly be ignored — the campaign level (and its name) is what actually matters for organization and reporting. The one legitimate use case for multiple ad groups inside a single campaign is split-testing near-identical variants of the same product (e.g. different images or listing versions) against the same keyword targets, isolating the variable being tested while keeping targeting constant. Outside of that use case, one ad group per campaign is sufficient, consistent with One-Product-Per-Campaign Structuring Principle.
Из тем: PPC Campaign Structure & Bidding