As Azure cognitive service official indicated :
Cognitive Services containers are an alternative to the Cognitive
Services cloud.Cognitive Services containers are an alternative to the
Cognitive Services cloud. Containers offer the same capabilities as
the corresponding cloud services. Customers can deploy the containers
on-premises or in Azure. The core AI technology, pricing tiers, API
keys, and API signature are the same between the container and the
corresponding cloud services.
So there will be no differences between between Azure Cognitive Service container and Cloud. And Azure Cognitive Service container provides customers flexibility in versioning and updating of models deployed in their solutions
If your data can not be used on Azure due to some privacy or regulatory restrictions or you are using massive data loads, which would either be too expensive or time-consuming to bring to the cloud or High throughput / low latency is required ,using Azure Cognitive Service container will be a great practice.