Nothing happens to the snippets on your phone. They stay in the app, and you can keep watching, editing and adding to them. What stops are the Pro features, like Freestyle projects and new backups.
Your 1SE Cloud Backup stays on our servers for 12 months after the subscription ends. Subscribe again within that time and you can restore from it exactly as before. After 12 months the backup is deleted, and the copy in your app is the only one left.
Once the backup is deleted, your account counts as having none, which matters if you also stop opening the app: see Inactivity and Account Deletion.