Ask HN: Data Grid as a Service?

I've been working on a Backend as a Service with a friend of mine but I've noticed that people would rather build their base application and then leverage other services for pieces they don't want to build. Search as a Service, Queue as a Service, Log-aggregation as a Service, etc... are very popular. I was wondering if a Data Grid as a service would be an interesting product to anyone. A data grid is an in memory data store that scales fairly well horizontally (there are a few open source solutions) and lets you join multiple "tables" to query seamlessly. The idea is that as you build out your application and system, you have more and more services and data sources. Exposing all of these to the clients quickly is complicated, you can build services that aggregate other services but that can be slow / hard to manage. You can shove everything into Redshift, Athena, or bigtable, but those are mostly for data warehouse uses and the querying isn't that fast. With a data grid as a service, you pipe your various datas into it via some queue (SQS, Kafka, etc..) or REST calls and then make queries to the data grid directly to retrieve data. It's kind of a cacheing layer on top of whatever infrastructure you currently have but allows multiple sources to be merged.

Is this a useful product?