As this already seems to support RegEx’es, which are much mightier than the usual, trivial “wildcard” characters “*” and “?”, I strongly oppose your suggestion, because this would be a huge step back.
But I fully concur that one should be able to enter all supported pattern matching strings, and it should be denoted which rules these pattern matching strings do follow (e.g. RegEx’es).
BTW, if the content of this field is always interpreted as a RegEx (regular expression), you should be able to use “.*” (i.e. any character arbitrarily often repeated) to achieve what the trivial wildcard character “*” does. I.e., reusing your example: +3967.*
P.S.: More details on this topic: