[Elecraft] USB vs RS232 for K3/P3

[Steve, K4FJ]

I have K3 radios which have been updated with most K3S add-on's, including KIO3B, but I am not currently usingthe USB capability.  I use RS232 instead.
What am I missing that is worth making the change to USB?  I have the cables to do it, but the current configuration surely works.
I have a passing interest in digital modes FT4/FT8, but I have not gotten that function connected properly.
Would changing to USB eliminate any need for Line IN/OUT connections to solve the digi problem?
The current cabling is a mess.
I love these radios!
73, Steve, K4FJ