I use components for everything and in my modeling I’ve never once found case where it makes more sense to use a group than a component. I’m in the minority though. You can make up your own mind about what to use.
Components end up in the In Model Components library. There is no such library for groups. Components can thus be saved into another library for use in other models later.
There are controls for setting component origin and axes so you can determine the orientation of the component and make it easy to insert exactly where you want it.
Components can be setup to glue to surfaces and to cut openings.
When you edit one instance of a component, all other instances within the model get edited, too. Even if there would be only one instance of the part in the model, making it a component instead of a group means you can leverage this editing feature if you need to make changes. There are several ways I use that to my advantage.
You can quickly and easily exchange components with new ones. Groups are more difficult to exchange.
In my modeling work, even if there is only one of a part such as a table top, there will ultimately be more than one copy when I create a plan document. One copy for the assembled version of the table and another for the exploded view and perhaps others for other views.
Some people who follow your current practice of making groups first and converting to components later complain that they have problems because they for get the haven’t converted the group to a component or they made it a component instead of a group and now editing one changes others they don’t want to change. Essentially it’s a lack of consistency that is creating frustration and wasted time. I don’t ever have that problem because I know they are all components. And I can keep track of when I need to make them unique.
Another benefit of components is that they remain in the In Model library even if deleted from the drawing space. If you inadvertently delete a one-of-a-kind group (maybe you meant to hit Hide instead of Erase) and don’t discover for hours, you’ll need to recreate the group. If it is a component, you can just insert a fresh copy of it from the In model library.
this is rare butI know of several people who had computer crashes and lost their work. In one case the fellow had only used groups. Although his file still existed, when he opened it, he had a blank drawing space and nothing to show for the time he had invested. The other guy opened his Sketchup file to find a blank drawing space but he had used mostly components. He found the components were still in the In Model library and he only needed to drag them out into the model space and get them placed. He did have to recreate his groups but it was much less work for him than for the first guy. Had he used all components, he’d have had even less work to do to recover.
As I said at the beginning, you decide how you want to work and what you want to use. My work flow works for me. You’ll find one that works for you.