The next most important reason why it is always better to get a back-lacing corset is a smooth silhouette. If you have just started waist training, there will be a gap between the edges, and there will be not many laces left after tying the knot. But as the gap starts diminishing, the length of the leftover lace after tightening will start increasing.
Here you need to make some strategies such as either getting a double knot or adjusting it somewhere else. Whatever it is, if you have lacing at the front, the bumps of the laces will show up on the dress fabric that you are wearing over your corset. Of course, if you have a stylish corset that you can wear over your attire, this will not be an issue. But if you are stealthing with the corset, the bumps of the laces can show up from the attire fabric, and it will make it obvious that you are wearing a corset underneath your dress.
When you have a back-lacing corset, you do not have to worry much about the bumps. This because such bumps of laces are not very much visible at the back. Secondly, people do not notice any such thing at the back of a dress. Finally, you notice a smooth silhouette at the front and at the sides of the dress you are wearing.