How or why do the REST endpoint responses differ from the gRPC reponses when querying GetTx?

[atharen]

It is well documented that the REST endpoint is now a front for the GRPC service (using gRPC-gateway).

This is also exposed in grpcurl:
$ grpcurl cosmoshub-grpc.lavenderfive.com:443 describe cosmos.tx.v1beta1.Service

cosmos.tx.v1beta1.Service is a service:
service Service {
  ...
  rpc GetTx ( .cosmos.tx.v1beta1.GetTxRequest ) returns ( .cosmos.tx.v1beta1.GetTxResponse ) {
    option (.google.api.http) = { get:"/cosmos/tx/v1beta1/txs/{hash}" };
  }
  ...
}

Now I am particularly interested in querying this endpoint with Go, for which there is also another documentation.

But I realised that I would have to RegisterInterfaces for all expected message types, which is acceptable for the default messages, but gets rather complex when modules are out of date like https://github.com/tendermint/liquidity, which does not support v47.

Then I noticed that the REST equivalent endpoint has everything that I need, and now I'm asking why does this work out of the box and gRPC requires unpacking/decoding, etc. (I'm sure i'm using it wrong, but I have to ask...)

Using /cosmos/tx/v1beta1/txs/44C8DAA0621CC441F2714A65025FD6410BE6351904C05FB46294B93F4C1E1D1E here is a snippet with messages from the full output:

"tx": {
    "body": {
      "messages": [
        {
          "@type": "/cosmos.bank.v1beta1.MsgSend",
          "from_address": "cosmos1tssqr446rmp692ltagnjh7xk36gdaq5w7y0eqf",
          "to_address": "cosmos1gzc54u4p67hh9r4m9vcml3ke9fc29tplsefy6k",
          "amount": [
            {
              "denom": "uatom",
              "amount": "1"
            }
          ]
        }
      ],
      "memo": "test1",
      "timeout_height": "0",
      "extension_options": [
      ],
      "non_critical_extension_options": [
      ]
    },
  ...

I did also attempt the RPC abciQuery endpoint, but messages don't seem to be included (reasonable since lower level).

TL;DR can I get the same output of the REST endpoint without dealing with unpacking messages?

---

To answer my question a bit, I think the Why of gRPC is this way is to enable functionality for interacting with applications, but for my use case, I just want to query the message in it's intended format.