It needs to be used early within 5 days of symptoms like Pfizer's Paxlovid, so testing will be important. Its efficacy however is only a 30% reduction in risk of hospitalization or death and not the ~90% reduction of Paxlovid.
There are some safety concerns with Molnupiravir and its efficacy is much lower than Paxlovid, so it may see more limited use.
They restricted its use to adults only as in animal studies there were changes to growth plates in rats. This isn't a concern for adults as growth plates aren't present in adults. And it isn't recommended for use in pregnant women as animal studies indicated there may be a risk of birth defects.
Interestingly it looks like they are implicitly preferencing Paxlovid here by the language choice. This drug is to be used if there aren't appropriate alternative treatments available. Even still there might be niche use cases for Molnupiravir over Paxlovid, especially as Paxlovid has a lot of drug interactions due to one of its active ingredients ritonavir.
Molnupiravir will have more supply available than Paxlovid, so it might see higher use initially until Paxlovid's supply becomes available. There will be several million courses of Molnupiravir available in January.
Both drugs can potentially be used together. This may reduce the risk of resistance emerging.