For the sake of argument, I'll take the opposing point of view. :)

'Hexagonal Chess can be played quite simply on a normal rectangular board'
is a statement not justified by the article. First the player is expected
to either rotate a board 45 degrees and remember that corners are now
edges and vice versa, or they need to memorize a new army unusual-moving
pieces. For the author of the article these may be simple tasks, but I
would venture to say that for the casual CV player it is difficult. The
author even implies this himself when describing the moves of the pieces:
'This is confusing' and 'This is a cumbersome piece' are used, and the
'normal' description of how the pieces move are complex.

The advantage of playing with hex-moving pieces on a readily available
rectangular board is outweighed by the complexities of 'biasing' the board
to match the connections of a hexagonal one. It would be to a player's
advantage to buy an inexpensive set of poker chips and arrange them as a
hexagon and use the 'standard' hexchess pieces.

The article is useful, in that it shows how one type of board and pieces
can be mapped to another type. It can provide the starting point for
further hex/rect explorations, and possible new pieces for the rectangular
board. 'Biased' pieces as described in the article are vaguely reminiscent
of left- and right-handed pieces in shogi variants. The rectahex knight
could be matched with a mirrored one to make a pair of 'ufos' on a
large-board variant.

Thanks for the article!