Here are a few reasons I use only components.
Editing one instance results in the other instances getting the same changes. With groups you would need to edit each one to make the same change to all of them. If you don’t want to be editing all instances of a component in the model, make unique is available. If it’s too much to get to it from the Context menu, make a keyboard shortcut.
For the majority of my models this gives me an ordered approach to detailing which translates into the processes in the shop. Four side table legs start out as identical, albeit flipped, components. All of the detailing (joinery, edges details, foot shaping, etc.) gets done to all of them by editing a single component. Only when it is time to get different details do they get separated. That’s the way I handled the legs when I redrew Ed’s table. Up until it was time to cut the dovetail sockets and small mortises on the front legs and the mortises for the back apron tenons on the back legs, the legs were instances of the same component. Immediately before adding those last details, I used Make unique on the back pair of legs to separate them from the front.
The Dave Method for very small objects doesn’t work with groups.
Axis orientation and origin can be set for components. This can make texturing easier, allows setting insertion point, makes it easier to get accurate dimensions in reports.
During creation you get prompted to give the component a name. You don’t have to give it one but you can. With groups they all get the same name. Outliner and reports are virtually useless when everything thing shown has the same name. You can go back and edit the names of the groups in Entity Info but that’s extra steps. If you don’t want to give components names just press G, Enter.
Consistency. Exact same process for every object. There’s never any question of what the object is. It’s always a component.
Some people say they make groups first and then, before they make a copy, they make it a component. That adds extra steps to the process and those same people frequently moan about forgetting to convert the group to a component before making a bunch of copies. They figure it out when the edit they want to apply to all of them doesn’t work. Since I only use components, I’ve never had that problem.
Or some people forget they made something a component and thought it was a group. Never a problem when I’m modeling.
I’ve seen others report these.
Fat finger Hide in the Context menu and hit Erase without noticing. The visual effect is the same but when you go to unhide the group 20 minutes later, it doesn’t come back. If you happened to have another copy of the group in the model space you can copy it over. If it was the only one, you’ll be redrawing it. If it was a component, meh, pull another instance of it out of the In Model Components collection and move on.
Computer crashes and your SketchUp file gets corrupted. I know of two different architects who had this expereince. Both burning the midnight oil to be ready for presentations early in the morning. In both cases, when they reopened their SketchUp files, they were presented with blank modeling spaces. Nothing there. The first guy had only used groups. He pulled an all-nighter to redraw the model from scratch. The other guy used a mix of components and groups. He was able to pull the components out of the In Model Components collection. He only needed to recreate the groups. He switched to using components instead of groups altogether.
I would agree but there are plenty who don’t agree. I’ve been using SketchUp for over 15 years now. Never once have I come across a reason to use a group over a component even for the non-woodworking projects I do. But there are many users who resist using components and only use groups. as you said at the beginning of your post, Simon, “different strokes.”