From
this website "Therapeutic indications
In the treatment of:
1. Napkin rash
2. Eczema
3. Bedsores
4. Acne
5. Minor burns
6. Surface wounds
7. Sunburn
8. Chilblains"
Lots of uses for barrier creams! As you correctly identified, it is more commonly preferred as a routine cream for nappy changes nowadays, for a child who already has nappy rash we tend to recommend metanium or bepanthen to treat it, and return to a barrier type cream once healed.
I guess for chilblains the aim is to sooth the skin, prevent the skin being damaged further by reducing moisture exchange (e.g. when washing hands if they are on the hands) and prevent infection (as sudocrem has a mild antiseptic effect).