Job security has to be considered too when someone has finally decide to start his bitcoin investment journey. One has to be certain that your job has to be really secured, and not a kind of job that won't last long. Job security should not be underestimated because if you have chosen to invest through DCA make sure that your job or source of income isn't something that's going to be terminated on a short run.
yes one can actually loss his job, that is life full of uncertainty, but at most time it is advisable to have passive income streams which one of it's enormous benefits is that it reduces the fear of job loss. It will become more easier for an individual to reach his financial goals when having a multiple streams of income by achieving them much quicker than if there was just one job, it helps in ensuring that you have a consistent and reliable source of income and at same time giving you that emotional rest needed to manage your asset properly.
I really don't think job security is paramount here in things to consider before investing into Bitcoin, because in life anything can happen, even the job you feel that is secure, they might just lay you off for no just reason, because life is unpredictable, and that is more of the reason why we should not play with our savings and emergency fund, because that is what going to keep you going till you get another job.