Not at all! Backups can be written on any storage that the parent system can see and has access to for writing data. While there are options for purpose-built backup appliances, they are not necessary, considering the wide array of virtualization and primary storage options available in today’s market.
It is, however, best practice to dedicate storage just for your backups and choose which storage works best for your recovery needs.
For example:
Backups that are required for short recovery time objectives (RTOs) are best kept on high-performance storage until they are ready for archive
Backups intended for immediate archival do not need to consume more expensive, high-performance storage and can be sent directly to tape or cold cloud storage
Solutions like the Scale-out Backup Repository from Veeam provide flexibility, which allows you to add any disparate storage to create logical extents for backup. Include cloud storage into the mix to take advantage of backup life cycle management from your on-premises high-performance storage all the way to archive in the cloud..