Which also means more expensive products. But consider this, Russian ballistic missiles just like U.S ballistic missiles have modern inertial navigation systems that make them more accurate than say what Iran has. So accurate ballistic missiles that are cheaper than liquid-fuelled ramjet powered cruise missiles, for conventional use can be made and used.
The core issue is that a ballistic missile has a predictable flight path... it is very much like a tennis ball or golf ball... once accelerated to speed it then continues along a predictable path and then falls to the ground. Now you can induce spin or other things to a golf ball or tennis ball to make it hook one way or another but the flight path can be essentially predicted with high levels of accuracy so interception is quite straight forward.
This means you will need to make them in large numbers to ensure some get through.
Air breathing scramjet powered weapons scoop the oxygen they burn their fuel with from the atmosphere and don't have to carry it around with them like Bulava or Topol or Minuteman, which reduces the amount of fuel they need to carry by 2/3rds at least... which is a huge saving in size and weight.
The problem of course was that a jet engine, like on a tomahawk or Kh-101 missile is that it is essentially a subsonic weapon because you would massively increase the amount of fuel burned trying to fly faster, but with a scramjet the fuel burn increase flying mach 9 or 10 is probably not that much worse than a ramjet flying mach 4-5, of course it might be 40% more but because you will be moving twice as fast it actually works out more efficient to fly faster.
Given the choice... most countries would prefer Zircon to Iskander.... Iskander is a solid rocket powered missile that manouvers but it takes an enormous flight range penalty with all that manouvering to evade enemy air defences.
Iskander and Zircon are both surface launched and Zircon is probably 2-3 tons, while Iskander is closer to 5 tons with half the range.
Ironically if you get the Iskander up to a moving start with a MiG-31K then its range and speed increases massively to 2,000km, while launching a Zircon from the same plane might give it a boost of perhaps 30-50% in range because it can already use its fuel burn and speed efficiently...