im on digi as well..

based on experience, vowifi works everytime im on wifi when overseas.. i made and received call while on vowifi and the standard local rates apply (RM0.20/min when call out to m'sian number, RM0.00/min when received call from m'sian number, etc. depending on what's ur telco charges).. received SMS TAC also fine regardless of vowifi or not

grateful that digi does not restrict vowifi to only works on malaysian IP.. long may it continue.. it saves me some serious ringgit as compare to before.. that i usually does not pick-up call (one that i deem not as important/urgent) if im not on vowifi.. or i call back at a later time when im connected