Improve wording around Celery

slides.md

@@ -754,7 +754,9 @@ class: flex justify-center text-2xl flex-col
         - If not Celery, then something else
 - That's not really the goal
     - Shared API contract is
-    - The built-in version will hopefully become great
+        - Interoperate with as opposed to replace
+        - Let you use the ecosystem which already exists
+    - The Django backends will hopefully become great
         - But must be done with careful planning and consideration
         - Django needs to remain the stable and reliable base it always has been
         - Don't want to burn-out the Django maintainers
@@ -776,7 +778,8 @@ class: flex justify-center text-xl flex-col
 - A common API
 
 <!--
-- Being built-in reduces the battier to entry
+- Why should this be built-in?
+- Being built-in reduces the barrier to entry
 - Integrating becomes much simpler
     - There's 1 API to learn
         - It will last you a while
@@ -939,7 +942,6 @@ background: /celery.svg
 <!--
 - Is this the end for Celery and alike?
     - Not at all!
-    - You've not made a mistake
     - It's a great choice
     - They have quite a head start
     - This is much more about usability and flexibility