I think this not only confuses users, but lessens the value of Zoho if they think they need to go elsewhere to do something that should work within ZCRM - or at least Zoho makes it seem like it should work, since Quotes are a module...
If Zoho has Quotes within the CRM system, as well as Zoho Invoice, which does quotes (and maybe Zoho Books, I don't know) - why another 3rd party integration?