Update docs/blog/_posts/2020-12-18-scala3-m3.md

Co-authored-by: Sébastien Doeraene <[email protected]>

Author: anatoliykmetyuk

docs/blog/_posts/2020-12-18-scala3-m3.md

@@ -81,7 +81,7 @@ Now, we have reverted to the following syntax:
 ```
 
 # `Matchable` trait – a new top-level type
-The motivation for this change is the fact that it is possible to access the underlying type referenced by an opaque type using pattern matching:
+Although opaque types are supposed to provide an opaque abstraction of their underlying types, it is currently too easy to break the abstraction using pattern matching:
 
 ```scala
 val imm = IArray(1,2,3) // supposedly immutable...