The 350 mOhm ESR is the spec that matters most for ripple handling: it limits the ripple current the capacitor can absorb before self-heating becomes a reliability concern. For a switching regulator output, the ripple current is I_ripple = V_ripple / ESR; at 350 mOhm, a 50 mV ripple translates to about 140 mA of ripple current, well within the typical derating for a B-case tantalum at 85°C.
The molded construction (Type Molded) provides mechanical protection and moisture resistance, though the part is not hermetically sealed — conformal coating on the board is still recommended for high-humidity or condensing environments.