In this case, the golf is not just for leisure. You'd have to dig out the XS to write a faster solution. On a large array, it's about twice as fast as using map, and about 50% faster than using (admittedly somewhat more readable) for and if blocks.

Also quite fast (though just a teeny bit slower) would be:

$_ = ($_ > 200) ? 200 : $_ for @array;
[download]

... though that might degrade quite badly on a tied array as it performs unnecessary extra FETCH and STORE operations.