As it's clearly stated here: Row-Overflow, Differential Backups, and More
Restoring a differential backup is essentially the same as restoring all the log backups in the period covered by the differential backup.
If you're using differential backups, a full database backup created before the first differential database backup is a must. It starts the chain. But the transaction log backups are not necessary. They only provide recovery to an exact point in time.
The differential database backups provide the recovery to the time when the differential backup was taken
The advantage of having differential backups is reducing the restore time. The downside is that they can take up more space than log backups, as they are cumulative, not incremental. They contain all the data that have changed since the last full backup, not since the last differential backup.
Here's a great example: Importance of how often you take full backups, check out the Example Strategies section