Yea from that standpoint I guess it makes sense but I don't really see why we need another Cloud to do that. Zack could arrive at Sephiroth simply because he is following Aerith and the rest of the party and he eventually gets involved there. I don't think he needs his own Cloud for thatIve seen this or more people acting like Second Cloud won't play a role.
Thing is a second Cloud makes a lot of sense when you think of it from Sephiroth lore perspective. As it stands Sephiroth doesn't give a shit about Zack, and even Zack's main rival was set up as Genesis.
Cloud though is a strong link between them both and if Cloud is traveling with Zack then it brings Zack to Sephiroth and the reverse as well.
The only thing I can think of is that Sephiroth uses that Cloud to convince 'our Cloud' that he's a failed clone and not a real person or something. Otherwise, two Clouds involved in the story could get too goofy to take seriously for a lot of people