But didn't the Romans view their emperor as a god?
Not until the late third century, and even then only sometimes. Well, it's really a bit more complicated. Some Roman emperors viewed *themselves* as Gods, but that is just a bad case of spoiled brat syndrome. However, the appropriate forms of religious worship, though, were very specific.
- Deceased emperors, if they were good, became 'divus' by senatusconsultum. A divus is raised to the honour of a God by men, not an actual God (deus) who is God through itself and by its nature. emperors also routinely referred to themselves as 'son of the divus XX' (the legal fiction of adoption could be made retroactive if necessary).
(Big problem for Christians - Greek does not recognise that distinction. 'Divi filius' is rendered 'theou huios', as in Iesous Christos theou huios soter'. In Latin, the distinction is clear.)
- Living emperors worship was a common habit especially in the Greek Easat (where Hellenistic tradition dictated the king was 'theos'), but didn't 'work' under the Roman tradition. What Romans were allowed to sacrifice to ('worship' is probably the wrong term anyway) was the genius of the emperor. that was the kind of tutelary spirit every person was thought to have. Children and other dependents would regularly make sacrifices to the genius of the head of the household, and by extension, all Romans could be thought of as dependents of the Augustus.
- Some Roman emperors thought that the Hellenistic idea of being outright gods with no strings attached was great. Caligula and Nero were the first, Aurelian made it stick. But these are extremes of a pretty schizophrenic tradition on the other end of which you have Tiberious slapping a citizen who called him 'domine' and Vespasian on his deathbed saying "Oh, shit, I'm becoming a God." (divus, not deus)