why does Sales Insight type also be supported for GetCampaignForSource

[Anonymous]

In the api document we can get  

Important: The Smart Campaign must have a “Campaign is Requested” trigger to qualify.  Its source must include Web Service API.

It says clearly that the source must include Web Service API . But why does Sales Insight type also be supported?
Is the Sales Insight the same type with Web Service API?
Is there any offical document make this clear? 
 

[Anonymous]

You'd set a campaign to be requested through Sales Insight when you want to add leads to campaigns from the MSI interface.  Details are at https://community.marketo.com/MarketoArticle?id=kA050000000KywGCAS

[Anonymous]

i mean the behave does not follow with what described in documentation