Google announced that accelerated delivery will not be available from Sep 17th, 2019. If you have chosen accelerated delivery for search and shopping campaigns, it will be automatically switched to “Standard delivery” as of October 1st. Google made this decision due to the poor performance of accelerated delivery.
The CPC was high and there was almost no control of when the ads were delivered. To add on to this, the ROI of accelerated delivery was pretty low compared to the standard ones. Due to high competition and exhaustion of budget during the early hours of the day led to a subpar performance of the campaigns. On the contrary, when standard delivery is chosen the ads are displayed throughout the day and makes sure that your daily budget is spent evenly. This is quintessential for advertisers with a small budget.
However, Google continues to have this delivery method for display and video campaigns. To provide greater control of ad delivery, it is recommended using ad scheduling. This provides the flexibility to the advertisers to adjusts bids or show ads during a certain period of the day.