Is it usual to use endowed chairs to support deans' administrative duties, rather than faculty's academic work? Our law school has (soon to be had) an endowed professorship that was awarded (on a 5-year rotating basis) to a faculty member with an outstanding record of research and scholarship, consistent with the traditional role of endowed professorships and chairs. The money in the endowed fund has grown sufficiently to transform it from a "professorship" into the law school's very first endowed "chair." At the very same meeting that the faculty was informed of this positive development, we were also informed by the University's chief development officer that this new and first chair would be awarded to the dean, not to increase his salary but to augment his administrative line of funds for travel, fundraising, etc.--a move consistent with our university's persistent shift of more and more resources away from faculty and to administration. The endowed professorship--awarded to a faculty member--will expire as soon as the current holder's remaining term ends in two years. 

The CDO maintained that it was usual to award the first chair to deans and not to faculty members, a statement that members of the faculty found to be ludicrous. 

Is it usual anywhere else for chairs to be used more often for administrative support of the dean rather than to recognize, encourage, and support faculty academic research and scholarship?
I only know how these things work in the natural sciences at R1 institutions, so my experiences might not be helpful for your institution.  

However, at my university, both the current and former deans of natural sciences were given endowed chairs when they arrived: the (former) dean Daniel Carson (see here) is the Schlumberger Chair of Advanced Studies and Research and Professor of BioSciences, and the current dean Peter Rossky (see here) is the Harry C. &amp; Olga K. Wiess Chair of Chemistry.  As you can see from his webpage, Carson continued to run a lab and churn out great research while dean (he finished his position in the spring of 2014), and I expect that the same will be true for Rossky (he just arrived and doesn't have much of a web presence at Rice, but here is his former webpage).  So it is not necessarily nefarious -- to hire really top-notch scientists into administrative positions, you have to offer them things.

But of course I have no idea what is going on at your university, and it could very well be a power play by the administration.