Asaik, yes

The cache.delete method only purges content of the cache in the data center that the Worker was invoked. For global purges, refer to Purging assets stored with the Cache API.

To purge an asset globally, you must use the standard cache purge options. Based on cache API implementation, not all cache purge endpoints function for purging assets stored by the Cache API.

Currently, it is not possible to purge a URL stored through Cache API that uses a custom cache key set by a Worker. Instead, use a custom key created by Page Rules. Alternatively, purge your assets using purge everything, purge by tag, purge by host or purge by prefix.