Fix readme

README.md

@@ -7,6 +7,22 @@ Wraps `eredis` and `eredis_sub` functionallity for Elixir usage.
 - Publishes binary messages to Redis Pub/Sub channels.
 - Subscribes to channels and calls a handler function when a message is received.
 
+## Why not use `Phoenix.PubSub`?
+
+Because multiple applications in many programming languages can use Redis Pub/Sub,
+but they don't serialize their binary messages according to `Phoenix` schema.
+
+## Why not use `eredis` directly?
+
+That's also a great option. With `EredisSub` Elixir abstraction we intend to hide
+Erlang specific knowledge, for example Erlang strings and OTP processes. We changed
+the API to let clients subscribe a handler function to a Pub/Sub channel, similar
+to how [`:telemetry`](https://hexdocs.pm/telemetry/readme.html) attaches handlers.
+
+We sacrificed flexibility on client process architecture, for a simpler mental model.
+If you need to handle message passing or a pool of processes, for example to handle
+heavier loads, use `:eredis` directly.
+
 ## Usage
 
 ### Publish
@@ -34,7 +50,7 @@ Subscribe to a channel:
 
 ```elixir
 metadata_example = %{subscribed_at: DateTime.utc_now()}
-EredisSub.subscribe("my_channel", {MyModule, :handle, metadata_example})
+EredisSub.subscribe("my_channel", MyModule, metadata_example)
 ```
 
 ## Installation