In an ideal sense, yes. Unions as we know them (including in this case[0]) tend to operate as separate entity / business. There are the employees, the employer, and the union. The three often have little or no overlap, so it just becomes another layer of communication / cost of business. They will likely be able to negotiate the things the employees wanted, but it comes at a non-zero cost to both sides. By contrast, if the organizing group had gone directly to the store management, what would the outcome have been? It's entirely possible it would have worked out the same, and it's possible they did that first - it's not mentioned in the article if their concerns were first voiced to management, or if they went straight to unionizing.
This is exactly what a union is. Employees negotiating with their employers as a group rather than individually.