It’s not really like MPI. It’s more oriented towards writing social software that communicates over the Internet, as a next step beyond ActivityPub. You could use it for a lot of things, but one example is to write federated software like Lemmy where you have lots of instances communicating with each other. But it makes things more flexible, you can really make any sort of social app with it.
DDG uses Bing under the hood for the main results, so it doesn’t really matter too much in terms of results.