there are chips without "inserts" that still have edge spots.

In general, edge spots are spots of color that can be seen when the chip is in the rack on a table or in a stack. The traditional clay and composite chips have edge spots that are actually the result of the manufacturer inserting bits of clay into slots in the base chip.

But there are lots of other chip types that have edge spots. In fact, I'd say most of today's modern chips don't have edge inserts at all, but have edge spots either as applied color, or as color injection molded into the chip. Look at most plastic BudJones chips, the Abiatti chips, and the Chipco ceramic chips. Most collectors will know what you're referring to if you call them all inserts, but most these days are not... they're just spots or designs on the edge of the chip.