In the West, they can not decide in any way in their attitude to hypersonic weapons. If the Pentagon intelligence report named Russia's hypersonic weapons as a direct threat to the United States, then in publications in individual journals it is said that, that hypersonic weapons are more of a "hype".
American organization UCS ("Union of Interested Scientists") published material, which states, that hypersonic weapons are being touted today as a revolutionary technology, but claims about the characteristics of hypersonic missiles are rarely confirmed by objective data.
From the material of the said Union, which includes both professional scientists, and popularizers of science:
These technologies began to develop back in the era of the Cold War., when the United States resolved issues of countering the USSR missile defense system. Today you can hear statements that, that hypersonic missiles are capable of hitting over-the-horizon targets in seconds, being practically unattainable for missile defense systems.
UCS calls this kind of hypersonic weapon claim "nothing more than hyperbole." – "Exaggeration of those properties, which this kind of weapon actually possesses ".
from the article:
If the US is to develop a sensible and cost-effective hypersonic weapons policy, they must first solve a few key questions.
The following are the same questions.:
“Does hypersonic weapons have strategically important advantages over existing missile technologies??»
“Are the current costs of these weapons commensurate with their strategic benefits??»
"Will US participation in the hypersonic arms race ensure the safety of the nation?"?»
The authors of the material believe, that modern hypersonic weapons can provide the performance of certain tasks, but only in the "niche" (narrow) segment. UCS is confident, that such a weapon is not suitable for a full-fledged existential threat.
from the article:
Hypersonic weapons are named so in connection with the ability to move at least 5 times faster than sound. But this is misleading. After all, individual ballistic missiles, which are available from the USA and other countries, at certain stages of the trajectory are able to develop speed, which is more than 5 times superior to sound.
Further, the authors point out that, that hypersonic weapons are often associated with gliding blocks - with the ability to fly at low altitudes and maneuver. But with such functions, as the members of the said Union write, also possess conventional cruise missiles. And such missiles can hardly be called an existential danger for an entire state..
The authors talk about the Russian Avangard and the Chinese Dongfeng-17.
Wherein, as noted, the likely motives for their possible use are constantly changing, what the UCS considers "confirmation" of the fact, that there is still more noise around hypersonic weapons, than unambiguous reasons for discussing its effectiveness.