Saving gas is important. If you're shipping gas or ammo by truck, you're creating targets for IEDs. Our casualty rates would be significantly higher if we couldn't use foreign drivers. The DARPA self driving car challenge was a response to the IED turkey shoot that's our supply line. At least we can avoid casualties.
The howitzer only offered "a few more tactical options", mainly being the ability to lay down accurate indirect fire whilst still being able to offer direct fire and defensive fire.
I mean why bother inventing gunpowder or rifling or any other weapons when an arrow killed people too. I mean sure the rifle was more effective and less competent soldiers could use it skilfully, but what was the point when we already had bows and crossbows?
So why bother inventing an accurate method of firing a frag round at 500ft when the M203 has a max range of 400ft and effective fire at only 150ft. Granted the AK47 is only effective at 250ft, but that still means the soldiers will be spraying and praying with grenade fire.
The whole point of making a weapon more accurate and effective is to increase the enemy combatant losses whilst decreasing civilian losses and soldier risk.
Additionally, they are working VERY hard to improve IED detection, and in fact are making quite a bit of headway in that regard. The same goes for every other issue you raised.
There's no reason you can't improve offense while simultaneously improving defense.
The US will have a significant advantage in developing jamming systems against these types of rounds.
The US isn't afraid of some Afghan insurgent living in a cave from developing a countermeasure against these new munitions. They're afraid Russia or China will be capable of developing a countermeasure. The rounds are worthless, or potentially dangerous, if you can cause premature detonation.
The fact that this particular weapon isn't useful in an IED attack doesn't mean that it's not useful for what it's designed to do. You seem to be under the impression there's no shooting going on in A-stan. This is definitely not the case.
It will certainly change the way soldiers will fight, but the advantage is that the insurgents and less developed nations won't have the technology and likely won't have the understanding of it. Everyone knows grenade launchers lob the round. However, it's going to be very different when it's got the range and the level trajectory of a rifle.
The XM25 autocannon is neat. Absolutely nobody denies this. It's also pretty useless, because any insurgent who engages security forces in a conventional gun battle is going to die. Nine times out of ten, they're dead; if by airstrike or just being outflanked and outgunned.
They know this, which is why for the last nine years, the weapon of choice used by the other side has been the IED or the suicide bomb; where high tech weapons like the XM25 are rendered entirely useless. While it's nice to see the Economist running an advertisement for Alliant Techsystems in their magazine, the XM25 will actually do very little to win CI wars.