From perldoc perlop:

If what's within the angle brackets is neither a filehandle
nor a simple scalar variable containing a filehandle name,
typeglob, or typeglob reference, it is interpreted as a
filename pattern to be globbed, and either a list of
filenames or the next filename in the list is returned,
depending on context. This distinction is determined on
syntactic grounds alone. That means <$x> is always a
readline() from an indirect handle, but <$hash{key}> is
always a glob(). That's because $x is a simple scalar
variable, but $hash{key} is not--it's a hash element.
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You can try the readline function rather than the <> operator. It is not clear to me whether you get all the default behaviors when using readline.