Buckley is on loan with the Championship side until the end of the season.
The winger joined Gary Rowett's side from Sunderland on an initial one-month loan, but that deal was soon extended meaning that the 26-year-old will now spend the rest of the season at St Andrew's (via Mail). And Kuszczak - who played alongside Buckley at Brighton - believes that the Blues are lucky to have a player of his calibre in their squad.
"He's a Premier League player," he told the Mail.
"He moved from Championship to Premier League which is not easy to do.
"You have to very good in this division to get a chance in the Premier League.
"Now he's on loan to us, and I think he's a big asset for us."
While the former Manchester United stopper is confident that Birmingham have pulled off a great deal bringing the wide man to the club, it is arguably fair to say that Buckley is yet to show the kind of talent that persuaded the Black Cats to give him a chance in the top flight.
He has scored one goal and is yet to register an assist for his current club. However, he could perhaps be forgiven for a slow start to life with the Midlands side as, before joining Rowett's men in January, his only appearances this term came during a brief loan spell with Leeds, so he arguably needs more time to get up to full fitness and to adapt to the system that Rowett wishes to play.
However, his teammate appears to have few concerns that once Buckley finds his feet, he will have no problem showing exactly what he is capable of.