What is a chess variant? Is it simply “related to, derived from, or inspired by chess” (attributed to David Pritchard on Wikipedia)? Chess960 fits this definition because it randomises the orthodox starting position. But this is all it does, an expert in chess endgame theory has also mastered the endgame of Chess960. What is important about this? Chess experts, including master players, agree that the endgame is just as important to the game as the former two parts, even intrinsically so:
"[I]n order to improve your game, you must study the endgame before anything else; for, whereas the endings can be studied and mastered by themselves, the middlegame and the opening must be studied in relation to the endgame." – José Raúl Capablanca (Emphasis in original.)
"... the endgame is as important as the opening and middlegame ... three of the five losses sustained by Bronstein in his drawn ... match with Botvinnik in 1951 were caused by weak endgame play." – David Hooper and Kenneth Whyld
"Studying the opening is just memorizing moves and hoping for traps, but studying the endgame is chess." – Joshua Waitzkin
"If you want to win at chess, begin with the ending." – Irving Chernev
“After a bad opening, there is hope for the middle game. After a bad middle game, there is hope for the endgame. But once you are in the endgame, the moment of truth has arrived." – Edmar Mednis
“David Pritchard, the author of The Encyclopedia of Chess Variants, wrote that the "complexity and beauty" of losing chess is found in its endgame.”Wikipedia, “Losing chess”
José Raúl Capablanca is especially important because he designed a variant with two fairy pieces, which create new endgame possibilities. So is Losing chess, which, in spite of introducing no new pieces, nevertheless has the possibility of an endgame with other than two Kings. In comparison, Chess960 merely changes the statistics of which orthodox endgames are more or less probable.