After using a bivy/tarp combo of various configurations for 15-20 years, I find myself rarely using them anymore (I do have eVent bivy that I still use in snow shelters in the Winter).
With the advent of the very UL dcf shelters, the weight savings are no longer there. They are spendy, no doubt- BUT you have a roughly 16 oz setup that includes a full bathtub floor, fully bug enclosed, room to sit up in, a vestibule to store gear & cook out of the weather if needed and only needs a small footprint to setup.
Too many upsides (except cost) to go back to a bivy/tarp for me.
With the advent of the very UL dcf shelters, the weight savings are no longer there. They are spendy, no doubt- BUT you have a roughly 16 oz setup that includes a full bathtub floor, fully bug enclosed, room to sit up in, a vestibule to store gear & cook out of the weather if needed and only needs a small footprint to setup.
Too many upsides (except cost) to go back to a bivy/tarp for me.