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.
A job is definitely needed to keep bitcoin investment right, if you are out of a job then you can decide to sell your bitcoin holdings if you face any danger. So this is why the job is special, you can keep your investment active in the Bitcoin DCA method with a portion of the income from the job. There must be an external source of income to meet basic human needs. Bitcoin holdings would not be sustainable for long without eros.
The emphasis is on source of income and not just a job. If your source of steady cashflow stops, you can resort to the emergency funds to sustain you while you look for another alternative. I don't know if you read within the conversation where it was started that to effectively invest in and hold Bitcoin, you must make sure you keep some funds for your basic needs, set up emergency funds and from the balance you consider investing in Bitcoin.
The emergency funds is actually for any danger than may arise when you are holding your investment. All the various improvement to the Bitcoin accumulation process is to ensure that the investor will be able to hold the investment and this is only possible when the factors that will lead to sudden selloff are eliminated.