One of the reasons why you need manual bidding even when you are using Google ads automation software is to keep your impression share high. You will most likely lose impression share due to low ad rank. When you need to increase your ad rank is to increase your bid. However, with automatic bidding, you cannot increase bids on terms you find key to your business.
You will need your business to appear at the top of the search engine results page. To do that, you will need to bid more on the keywords you consider ranking higher for. Using adwords scripts for bidding does not allow you to selectively bid on specific keywords and here is where you need to manually bid on keywords.
Match keywords will see your tank higher on SERP if you bid higher on them. Tiered or stacked bidding is not possible with most adwords automation software tools. This way, you will have to get into your campaign and manually bid more on match keywords.
Google ads automation can help you avoid exorbitant bids but you still need to be sure that your budget brings in results. While you can avoid exorbitant bids by setting a lower limit for clicks, you still need to manually see the bids that are taking your money even when you are using adwords software.
If you need to lower the costs you incur to convert; you need to be more involved with how your ads run. It is advisable to automate for business in the United States and Australia but you also need to be more hands-on even with adwords automation tools. Combining Google ads scripts with manual ads maintenance will give you the results you need.