Difference between Attachment and Document library in MS CRM 2011

As we all know Document Library (Sharepoint) integration is a very big hit in MS CRM 2011.
That means we can very easily use the advantage of Sharepoint, by using the component.
Also the OTB attachment facility it still available in MS CRM 2011.

So what are the basic differences in these two?
below table will make it a bit clear...
so its upto the users and the implementors how to use it as per the requirements..
mainly if we need any version system to the docs then better go for Sharepoint, even if it will cost extra.

MS CRM 2011	File Attachments	SharePoint Integration
Need user Account & Licenses	only need for MS CRM	need for MS CRM as well as for Sharepoint
Stores documents in Microsoft Dynamics CRM database	Yes	No
Can take documents offline with Microsoft Dynamics CRM for Outlook with Offline Access	Yes	No
Uses Microsoft Dynamics CRM security roles and settings	Yes	No, SharePoint security settings must be configured separately for the corresponding site. so need users to be added.
Single backup process with other Microsoft Dynamics CRM data for documents	Yes	No, Sharepoint must need to back up in addition to MS CRM and restored and configure.
Additional software required	No	Yes, Microsoft Office SharePoint Server
Check in and check out Facility	No	Yes
Version Controland revision tracking	No	Yes
Can search for content within documents	No	Yes
Can configure alerts for modifications	No	Yes

Regards,
Sudhanshu