boxwood makes a fine wood for carving but not so good for planking. you can use it and it does work BUT Boxwood is brittle and you will snap planks trying to bend them around the bow. The very best wood for planking is pearwood and not the steamed pink stuff but rather natural pearwood. This wood is very close to the same color as boxwood but takes a extreme bend.
Some like boxwood other don't comments, is boxwood has no feature or figure it looks like plastic rather than wood. Those who use it will polish it to an ultra fine finish.
Then the cost of $30.00 a foot and up where as woods like pearwood, cherry and many other woods are in the $4.00 a foot range. Is the high cost worth it? well not for planking but for things like caprails, fittings and carvings I would say yes.
using light colored wood as planking will show off every seam and joint far more than a darker wood so your planking job will have to be tight and right on.
model builders will use exotic and expensive wood to increase the value of the model. However, there are dealers and galleries out there that do not accept Castello boxwood as boxwood. As a matter of fact they are correct Castello boxwood is just a trade name it is not boxwood or anything even close to boxwood.