The problem is 3-fold.... This is supposed to be kind of funny / entertaining.

1) Damonites (Damon is one of many self-ligating systems) will very often defer phase 1 treatment if they think they can do more in phase 2.  I actually agree with this by and large... except when they defer... they are not looking at the whole-health.  A few offices  are rare exceptions.  Some offices do use CBCT and sleep questionnaires/screenings.  (can probably count on 1 hand!)  This is not the norm, and there are liability reasons for this as orthos are not doctors.  Because they are NOT looking at whole health, the child's behavioral and brain development (including staving off what potentially classifies as ADHD) can get left behind.  Obviously expansion should be tempered to only what is needed as it's relatively easy to expand a palate and you can overexpand and not be able to retract.  Just orthodontists generally don't take a whole health assessment and Damon providers (especially those who frown on RPE) defer to phase 2 far too often, where these early intervening years are life-changing!  Even just 1-2 mm of arch-widening can make a health difference.  I saw it firsthand.

2) The main concept is light/continuous pressure... the thing is that Damon can pull teeth away from center of gum mounds.  Check this... https://ormco.com/products/damon-system/studies/freedom.php  If the teeth are centered more in the gum mound, less chance of perio/gum problems.  There may be ways to combat this.  I just never saw it myself and only have their literature to go off.  In fact, this may be one reason why the Damon smiles are so pretty.  If the teeth are on the outer-rim... it's a pileup of white teeth!  So pretty, sure... but what about perio?!  The gums don't appear to support as much.  Just because something is pretty, doen't always mean it's healthy.  It is pretty to have a very wide maxilla... but you can overexpand to the point the back molars don't touch.  It may look pretty, but eating is important.  Ultimately, healthy is pretty.  If you have the type of personality to brush every day... you're probably okay.

3) Can worsen asymmetries.  Am I the only one noticing all the asymmetric Damon smiles?!?!?!  Apparently not.  The lips will pucker on the left or the right or in the middle.  The reason they pucker is because the teeth are floating around on the outer rim and fighting the lips (lips lose this battle).  And because of all the shifting... the smile pileup (lip curling) ends up on the right, left or center.  Usually it's not even.  Sometimes you'll see a guy spit out patients who all have smiles sloping to one side.  Depending on who it is, I literally can look at someone's lips and tell if they had Damon braces.  I just can.  For a guy who has fat lips that curl outward to begin, I may consider alternatives.  Sometimes they curl away so bad that there is like a centered divet where it kind of hits the skin.