The phrase "are far less useful" is correct and usable in written English.
It can be used when comparing the usefulness of two or more items, indicating that one is significantly less useful than the other.
Example: "While both tools have their merits, the older model are far less useful than the latest version."
Alternatives: "are considerably less effective" or "are much less beneficial."
Although self-reported abdominal symptoms may be of use for screening large populations of young children, they are far less useful on a smaller scale.
In return, the West agreed to provide North Korea with two light-water nuclear reactors, which would supply electricity but are far less useful for making nuclear weapons.
The sound system is more powerful and less complex than it used to be, although it still has arrow buttons for tuning the radio, controls that are far less useful than knobs.
The academic's favored programs are far less useful in practice than in research, due to the requirements for testing and validation in the case of design with a view to plant construction.
Marine ecologist Larry Crowder of Stanford University in Palo Alto, California, says that fisheries data are far less useful when aggregated, especially when trying to devise new approaches to management.
You can also create documents with the app, but it is far less useful for that purpose.
The PlayStation 4 also has a camera peripheral, but it is an optional, sixty-dollar add-on, and is far less useful.
Analyzing who did what in the last 10 years is far less useful than discussing what, if anything, can be done in the next 10 years.
But in Westeros, as we have seen, information is far less useful than a big stick, and the calculation is always a simple one.
But if Amazon folds its apps, or if you decide you want to read your books on another e-reading app, the books will be far less useful.
Thus, seizing the physical device itself is far less useful today that it was 10 years ago.
