To give a bit of context, I graduated 1 year ago from an undergraduate where I double majored in Math and Computer Science and I am planning to apply for a CS PHD this coming year with a focus on theory.
During my undergraduate studies, I worked on a project with a Professor that lead to a publication in a top Information theory conference (although the paper was about an information theory problem, it was essentially a theoretical cs paper). In addition, we added a new results and submitted the result to a top information theory Journal and we got the paper accepted. The last "breakthrough" came when I was able to come up with a new optimization technique that was interesting from a CS theory point of view, which led to a CS theory paper.
However, after writing the paper, my advisor told me he would prefer to submit the paper to a journal ("Theoretical Computer Science Journal") right away, rather than to a conference.
I understand that in CS, conferences are generally preferred to journals, but my question is, assuming that the CS theory paper gets in, would I be disadvantaged during the grad school application process against someone who has, say a SODA, paper? Are journal papers really viewed as strictly inferior to conference papers?