It's not "necessary". It's never "necessary" to use objects. There are fine languages that can do anything Perl can, without having objects.

That doesn't mean you cannot write good code that just has one instance of a class during the life time of the program.

Whether having such a singleton is a good idea depends partially on the (sub)goal you are solving, but mostly on you, the programmer. If you feel comfortable using a singleton, by all means, do. If you don't think it's appropriate, don't.