Your two points (in reverse order) are,
"I do agree with the "similar appearance issue". But doesn't that hold true for a paper passport as well?"
"The radio frequency/output is just as useful as a mugger looking at a persons clothes/jewelry/or some other appearance. And that's cheaper. So, using that as an "issue" is a stretch."
The first point, is the real problem with e-ID documents (ie human weakness), the second is where ID dealing will become quite lucrative as a criminal activity.
First problem with e-ID doccuments and the credentials they are contained in is the "weaklink human". So much so that e-ID is probably going to actually weaken security.
Currently the person checking passports will look over the passport with an experianced eye and it takes a reasonable quality fake to get past them.
However with e-ID credentials the employer of the checker has no reason to ensure they can spot a fake paper document any longer. The checker becomes totaly reliant on the "reader" machine as the validator of the e-ID not their own eyes and experiance. Also there will be preasure from the employer to speed up checking as an "efficiency measure" so there will be less and less time for less and less experianced checkers to look for fakes.
Further also in the name of "efficiency" passports will have less and less printed security measures. This is simply because they are expensive to implement and as far as the powers that be are concerned a waste of resources as the e-ID is "mathmaticaly secure and unforgable"...
So within a few years even a quite shoddy fake passport that has a valid chip and cloned signed e-ID documents will get through, whereas in the past the person checking would actually have taken a serious look at the document in their hand and it would not have stood a chance.
So at the end of the day all the e-ID is going to do is actually make the current level of security of the credential less.
Which brings me onto your second point,
It depends on where the mugger is and also what they are after.
In an area where business is the main cause for visitors from abroad it can be quite difficult to tell visitors from locals as the dress style will often be similar (it helps deals go through if you look and act like a local).
Importantly if the mugger is "identity dealing" then the passport is the main object of interest, any money or other easily disposed of valubles are either "extras" or "window dressing" for the stealing of the ID.
The best thing for the ID dealer / thief of the future is that the passport gets returned to the owner with the minimum delay possible.
If the "target" can have their pocket picked, the ID page of the passport photographed and the signed e-ID documents required for cloning read out in a few seconds and the passport put back in the targets pocket without their being aware then so much the better as there is no (real) liklyhood that an alarm will be raised.
Although "Identity Dealing" sounds a little far fetched it is actually currently quite a lucrative business for the likes of "call center staff" in "out sourced" bank operations run in other countries where the 10USD price per solid ID represents a considerable fraction of the daily wage.
Getting copies of signed e-ID documents and a photograph of the ID page of the passport would easily be worth 50USD to an "ID Broker" and have a sell on walue of 500USD or higher.
Finaly "biometric" ID you have to ask yourself a serious question, will it ever actually be reliable or even take off?
Currently just about all proposed methods of biometric (finger print, DNA, eye scan) have significant problems. DNA is not practical due to the length of time to actually check it. Eye scans are seen by Jo Public as being way to physicaly intrusive and have issues to do with contact lenses infection etc.
This leaves fingerprints as the front runner unfortunatly as has been demonstrated on many occasions they can quite easily be forged providing you have a reasonable set of "original prints" to work from (think what you leave on a beer glass, knife and fork or any other ordinary every day object with a clean smooth surface such as a glossy mag, briefcase).
Getting a persons fingerprints without their knowledge is actually not that difficult and simply adds a minor extra hurdle to an "ID dealer / theif".
At the end of the day reliable ID that is efficient in use is a very very difficult if not impossible problem and E-Passports are not even close.