Some of my initial thoughts...
Benefits:
* Accurately track and analyze trends against local calendar days, such as:
- Enabling day of week bid strategies
- Measuring the impact of promotions (that start/end at midnight in each market)
Detriments:
* Other engines do not offer this - so, combining all SEM stats for a specific market would be layering stats for different time periods (also requires internal sales data match... for Google sales - market time, for all others - local time)
* Prevents grouping by language, where there may be multiple time zones at play
Any other thoughts?
So, in summary, setting your account's local time zone means it will affect the entire account, including all ad serving, reporting, analytics, and billing, which will be calculated and managed according to the selected time zone. If you don't select a different time zone, your account will remain on Pacific Time.
If my understanding is correct, this change is in preparation for the "Dayparting" facility which will enable setting times to feature the ads to display, and times to hold ad display. Whilst the idea is perfect for a country-specific business needing only to sell to a country-specific audience in standard business hours, those selling internationally will not necessarily require the feature.
How about its use over the weekend? Bear in mind Sunday in Israel is a working day, so that only leaves Saturday.
I'm also thinking that many businesses will disable their ads at intervals, enabling those with unchanged and constantly running ad programmes to better feature their ads while others are turned off. This could be beneficial on an unchanged campaign.
It will also mean that the Adwords stats will vary as the impact of the Dayparting comes in.