It would seem foolish to start developing on a version without on-chip debug
since no reply "I use it" has been forthcoming, I suggest you get a dev board and try out their software re on-chip debug before you lock yourself to this chip.
Quite a few of us use the SILabs offerings and seemingly are quite happy (I am, an not speak for the rest) with the on-chip debug these chips provide and the associated software.

Erik