Query about the Amount of Multicast State information

Hi Folks,

The amount of State information (especially S,G) seems like a big concern,
when I am referring to Multicast texts / trainings.
I am unable to understand why? I mean Unicast routing table can handle full
BGP prefix information. Then why is "Large amount of Multicast State
information (S,G) considered such a big deal"?
Can't the Multicast table handle it? OR What?

Please let me know about your views on this. I am not able to get it.

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Thanks & Regards,
Adesh
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