There are a few disadvantages to Performance Max campaigns:
1. Low Level of Control
PMax campaigns aren’t without their limits. They offer the benefits of customization, efficiency, and a high scale level (through the inventory acquired from partnerships). In reality, they can still feel restrictive compared to search or display campaigns.
The primary drawback to running PMax campaigns is the low control advertisers have over their targeting and performance data. The campaign manager’s ad server doesn’t let advertisers access keywords or audience data.
Users can’t add negative keywords or use smart bidding strategies in PMax campaigns. You must rely on your campaign manager for these tasks instead.
What usually happens is that most of the budget runs through branding terms because it aims to provide the best performance which, usually, is strictly related to brand terms.
If you want to keep strict control over where you bid, keep regular campaigns like search or shopping and use automation tools like the ones that Google provides or automation tools like OrbitalAds.
2. Impossibility to Add Negative Keywords
You can consult with your Google Ads representative to have negative placements and ad groups added. This method includes negative keywords, audiences, placements/URLs, topics, mobile apps, in-market categories, demographics (age and gender), household income, or parental status.
Consider switching to manual CPC bidding or setting a maximum cost-per-click (max. CPC) bid limit to ensure you’re not exceeding your budget with an automated bidding strategy. Using max CPC bids instead of automatic bidding will keep you away from Google’s help in optimizing the campaign. Especially in promoting it according to what the advertiser needs.
3. Difficulties Analyzing the Source of the Data
When looking at the data from a PMax campaign, you’ll want to see how the keyword or audience you’re bidding on is performing. This result may be difficult with keywords or audiences when there isn’t enough traffic for Google to separate which clicks came from what audience.
It will group your data in the “Other” category if this happens. This problem makes it hard to determine which keywords are performing well and which audiences have produced good results.