Your interest appears to be triggered by the availability of "great online programs now", rather than the demand for people with this degree, which is a worrying sign.

Obviously, for some people and jobs, this degree is a great idea. Still, I suggest you look at the demand side as well as the supply side. How many job ads can you see with this requirement? What are the employment statistics like for people who currently have this degree, or previously graduated from the programs you are interested in?

Often, employers basically want someone who is minimally qualified for a job, and you don't really get any extra points for experience / qualifications beyond the minimum, and indeed it can count against you.

From this comment it seems you are intending to pursue the masters while working. So the opportunity cost is not lost salary. Your opportunity cost would be measured more in time and stress. You will be giving up social time. If you are single and don't have children and are young enough that the masters degree has time to payoff, then I would encourage you to go for it.

Also, since you really enjoy both theory and hands on coding you are well situated to get maximum benefit by applying theory to real problems.