However, this implementation has advantage of using the tied variable as constant in a string which can be interpolated.

And the benefit of interpolating a compile-time constant into a string at runtime is?

use constant AVO => 6;

...

print "The constant is " . AVO . "\n";
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Or

printf "The constant is %d\n", AVO;

print "The constant is ${ \AVO }";;
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