It can make a difference depending on what's in "...".

Compare

BEGIN { eval 'sub foo { return 2 }'; }
my $i = foo 3;  # my $i = 2;
print("$i\n");
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with

eval 'sub foo { return 2 }';
my $i = foo 3;  # Syntax error!
print("$i\n");
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Compare

BEGIN { eval 'sub foo(\@) { print(@{$_[0]}, "\n"); }'; }
my @a = qw( foo bar );
foo(@a);  # foobar
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with

eval 'sub foo(\@) { print(@{$_[0]}, "\n"); }';
my @a = qw( foo bar );
foo(@a);  # [undef]
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Compare

BEGIN { eval 'sub foo { print("foo\n"); }'; }
BEGIN { foo(); }  # foo
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with

eval 'sub foo { print("foo\n"); }';
BEGIN { foo(); }  # Dies. Can't find foo()
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etc.