Some employers (though not necessarily all) value traditional face-to-face education and will automatically move your application to the bottom of the pile when they learn that you completed your degree online. In my field online programs simply don't get accredited - there is too much of the training experience that requires a physical presence: showing up, collaborating, meeting face-to-face, etc. Social work is a bit different. However, I don't know what your fieldwork/practica would look like in an online program. You should find out whether the type, quality, and quantity of practicum hours are comparable to those of conventional programs. Be honest with yourself. Good social work jobs are competitive and you want to position yourself well.
There is also something to be said for making your professional education a full-time, immersive endeavor rather than something you fit in on evenings and weekends. That may sound a bit privileged, but if you're an employer with 100 applications to sift through, it's a way to cut through the pile quickly.