Disaster recovery is not just about your server failing and having a backup, its an integrated plan that allows the business to carry on in the event of a major event.
The part DTS plays in this plan has to reflect actions to mitigate a disastrous event.
A disaster recovery backup that can restore a server to the last backup, is sometimes as simple as a disk that gets taken off site everyday. In the event of a disaster a new server is brought in and the backup restored to it, though this can take sometime and is not as quick as the next solution.
A replication of your server to the Cloud. This product called DTS Replication constantly syncs your server to the cloud, in the event of a disaster the cloud version can be enabled and accessed from any location with an internet connection via a secure VPN or Terminal Server if you have one. As this can be set up and running in hours the down time is minimal. The replication solution can be seen as a hybrid solution and this is recommended by Microsoft as a more robust solution.
Office 365 online mailboxes and Onedrive may also need to be backed up, whilst there is recovery of items up to 30 days within the system, some files and emails are not recoverable after that time, we would recommend a backup solution to reflect that issue.
If the business has more than one site it may be possible to have a server at each site to replicate against disaster, this is a good solution if the Cloud is a problem and there is reasonable internet provision at both sites.