Hello Nguyen
strongSwan has some EAP and mobility extensions that can be useful for enterprise networks. However, the reason why you would use strongSwan for such a connection is primarily because it is a software package that has widespread use, and you will see it frequently in corporate networks. For this reason, it is a good idea to understand how to interconnect with it, as you may be called upon to make such a connection. Because it is well documented and maintained, it is likely that you will encounter it in the marketplace.
Although much of what strongSwan does can be done with a Cisco ASA, it is always good to know how to interconnect with devices of other vendors.
I hope this has been helpful!
Laz