"principal merits" is a correct and usable phrase in written English.
It refers to the main or most significant qualities or advantages of something. Example: "When evaluating candidates for the position, we will consider their principal merits, such as their experience and qualifications."
Indeed, one of the principal merits of this approach, as the White House no doubt understands, is that it gives congressional Republicans fits.
Its principal merits lay in the avoidance of any reliance on causal concepts and in the ability to give an account of explanation in areas of theoretical science in which talk of causation seems strained.
Westley describes the U21 League as "a small step" to bridge the gulf, its principal merits organisational; the games are staged at the weekends to complement a first-team schedule, and the league is national, not regional, as was the now-scrapped reserve league.
The principal merit of "Hallelujah Junction" was contrast.
As for Bush's speech, its principal merit was that it provided a pretext for Webb's.
The principal merit of the vacuum spark source is its ability to produce copious quantities of ions of all elements present in the electrodes.
More to the point, a show may be small in scale without being small in the scope of its attention, and it is the principal merit of this exhibition that large issues are raised.
The principal merit of ATM was that the promising infeasible individuals could be inherited into the next evolutionary process.
Compared to other models from the literature (e.g. McDougall and Hungr, 2004), the GeoFlow_SPH model has the principal merit to explicitly introduce the hydro-mechanical coupling between the solid skeleton and interstitial (pore water) pressure, the latter one being variable within space and time.
The principal merit of the book is that young physicians can rapidly find up-to-date practical information.
The principal merit of this approach is that gene concatenation allows for the minimization of statistical errors, often resulting in well-supported trees (Delsuc et al. 2005).
