How do you measure success of Google Maps in shopping mall?

Clarification - 
1-What is the user goal?
User is trying to find the mall 
User is trying to find a shop/restroom inside a mall 
User is trying to find shops with offers in the mall.
user may be looking for popular places or reviews of shops 
User may be looking to go out to home or some other place


2- Where is the user located when they are using this feature?
Inside the mall
Outside the mall 

3- Since the user is inside the mall, can we assume that the user is on the app? - Yes

4- Is there any specific feature to look for shops when inside the mall? No, users will use the normal google maps search feature.
 
Customer Goals
1- locate a shop/restroom inside a mall, probably go there

Company goals
1- Increase user engagement so that there are more opportunities for advertisement 

Metric for the user goal
M1-Users are aware of this feature 
M2-Users are using it 
M3-The feature works
M4-Users find it useful 
M5-Users use it again after the first use

Metric for company goals
M6- User engagement time for user segments using this feature vs not using this feature  

Other checks
M7- User engagement doesn't get impacted for users who are using this feature
M8- User engagement doesn't get impacted for users who are not using this feature

M1- # Search queries of places inside the mall while the user is inside the mall 
M2- Is also covered in M1
M3- # of search Results where the top 1 result is inside the mall / M1
M4 -# of times users click on start navigation/ M3 numerator
M5- #of times users reach the searched place/ M4 Numerator

M6- Avg engagement time of users using this feature should be ideally more than users not using this feature.

Reason - This is an additional feature for the existing user sets and hence should increase their avg engagement time. 

The drawback of M6- It may also be possible that the feature is very complicated and hence avg engagement time is increasing. So, we should also look at avg sessions by the user using this feature vs average sessions by users not using this feature.

M7- M6 captures the same point
M8-As there is no separate feature for this usage, it is not going to impact users who do not want to use it.