ONe thing not mentioned in Charlies minatures is the skill building that this develops. When you can cut a cove or bead or crisp V detail in a miniature it teaches you an awful lot about tool control. This makes it much easier to turn really crisp details in larger pieces. (Larger being relative since some details in my Christmas ornaments may be 3/32" or so)
The same is true for getting the form correct. It takes very good tool handling control to really nail a form correctly when the piece is 1/4" in diameter. This carries over to larger work very effectively. I have no trouble at all taking off a few thousandths of an inch to fine tune the shape of a box now that I've made pieces that only .025" tall.
You don't have to go that small of course. Try making doll house scale pieces. An 8" candlestick would be approx. 3/4" tall and have some really fine details to turn that will do wonders for your skill building.
You also don't need really small tools. My friend Jim Greenwood often does doll house scale pieces with a 3/8" bowl gouge. It's all about the cutting edge, being on the bevel and very light tool tool control. I should mention that you won't be on the bevel cutting a 1/8" cove with a 3/8" bowl gouge. That has to be a scraping cut but you can get buy with it on this scale if your delicate enough.