no big difference. If it's a Tool, you select the tool first and then select the curves in order and hit Enter to create the loft surface. As an action, you select the curves first and then select the Loft command and it creates a loft surface.
SimplyMaya specialises in Maya tutorials. We offer over 1,000 individual Maya training videos, ranging from basic Maya tutorials through to intermediate Maya tutorials. Our tutorials are created by instructors with industry experience and are designed to get you up and running in Maya quickly without making it seem like hard work.