Sql server database restore vs index rebuilds
That doesn't make much sense.  If you restore a database from a time earlier, you won't be capturing data that has changed since the backup. (but I'm assuming you mean a backup directly followed by a restore)

If you're talking about taking a full backup and then immediately a restore, then you will persist the fragmentation in the restored database as it was when it was backed up.

So either way I will say no that is not advisable.  Prudent index rebuilds/reorganization based on the fragmentation is best practice.

See this blog post that on database restoration and index fragmentation that debunks that myth.  Restoring a database also restores the fragmentation at the time of the backup.