Covered more in the blog, also:
Firstly, we have added two options to replace the ambiguity and confusion caused by the use of asterisks as wildcards. Take this source URL as an example:
*.example.com/a/b. Would you expectwww.example.com/a/bto match? How aboutexample.com/a/b, orwww.example.com/path*? Asterisks used as wildcards cause confusion and misunderstanding, and also increase the cost of implementation and maintenance from an engineering perspective. Therefore, we are not implementing them in Bulk Redirects.
Asterisks as wildcards are ugly from a semantics perspective, and we didnt want to carry that forward into the new product.