No it is not.
You're deciding from an IT perspective where is the best place to offer a certain type of request.
How will you explain that to end users?
The point here is not about " best fit purpose according to IT administrator".
It's about having a user friendly self-service and auto provisioning system.
Going your way, you will need a help page to explain wich type of request is in wich tools.
Ex : If you need to buy a licence for Software A go to Catalog but if you need help to setup software A go to ServiceDesk to request help or look at knowledge.
It does make sense from an IT administrator pov, but Rita, 56 years old from sales dept, will find it confusing and will not use it.
Pretty sure you'll have a hard time with user adoption and no wonder why so much ITSM projects fail.
I'm not sure about your experience in implementing ITSM solutions but it is not a scenario that any of my client would have accepted.
In the end, do not take it personnaly, I think that both of you are very knowledgeable in CA Service Management solution but those advices, that have more to do with functionnal architecture, were out of track.