The answer to your question is easy: "Depends".
Depends on many factors like, how complex are those applications that you are building? Is there a better technology suited for implementing those applications?
SwitchYard is a Service BUS, but also it is a framework to develop applications, so you can have a combined approach where your CRM, B2B, InventoryManagement, etc.. are also implemented in SwitchYard, but not deployed on the same servers. You can still expose this applications via a REST API and consume it via a central SwitchYard acting solely as a BUS, and allowing you to decouple your Business applications. Of course, if there is better technology suited to develop a CRM, then use it and connect it to the rest of appplications throught the central SwitchYard BUS.
The good thing about SwitchYard is that it allows you to create complex Business Applications (it has BPMN, Camel, and Java components) and leverages all the capabilities provided by the JEE server it runs on top, so also EJBs, MDBs, CDI,... If your application can be easily built with this, it will simplify your life (development/management/monitoring,...) having an heterogeneous development platform.
But any solution is fine. That's the greatness of SOA.
I don't see the advantages of implementing the application based on switchyard rather than developing on other frameworks. Of course, nobody force me to do that. But I just wonder: is this the wise choice if we implement the business service based on SwitchYard? Let say about how complicated the business service would be, technology tight coupling, infrastructure tight coupling...
There is advantages in terms of what SwitchYard provides to you out of the box. Of course, and as I said, it is a matter of taste. If you know Spring, if you are familiar with Spring, then you can do your app with Spring and deploy it into any server, but if you are familiar with SwitchYard, BPM and camel, then SwitchYard leverages you a lot of capabilities.
I've seen people doing huge Order applications in SwitchYard, so it fits perfectly for them.
The good thing of using one technology is the learning curve, but if you have already passed that problem, and are familiar with many different technologies, then the one that best fits for you is the best ;-)