If I was in your position, I would apply for a RC asap. Most people are doing this if they will not achieve the 6 years of EU law they needed for settlement before spring/summer 2019, when EU law will be put into UK law and the UK will remove what they don't want.
Some think it might be only those with an RC that get an offer to stay under the Brexit negotiations and it is worth getting one just in case. Plus the UK is also talking about of a cutoff date and your RC will give you a date on the UK records. Nobody knows yet about the offers, but it won't hurt to have an RC.
The other thing is that since June 2016, your employer can now go to jail for employing an illegal worker and they like to see proof that non-EU citizens has a right to work in the UK. Not that the RC is proof of that as it becomes invalid if your EEA citizen ceases to be a "qualifed person", but I assume it might enough to keep the employer out of a criminal record if he isn't told this by the non-EU citizen.