Why buy a micro game when you can buy the board game for less money? Answer: because a game as good as this Psion version of Backgammon can be more enjoyable than the original.
The graphics can be better than the original board and counters. These are. The computer may play better than your normal human opponent. This does. A micro game might teach you how to play, but a board game can't. The demonstration mode and suggested moves of this version make an excellent tutor.
You can cheat in the board game. You can cheat the program by playing your move again. And again. And again - until you think you've got it right. And even then the program will probably defeat you. I found it easy to beat at level one, but could not beat it at the highest level, four.
You have the option of throwing the dice yourself if you don't trust the Spectrum (it throws some very lucky doubles), so you could cheat by feeding it false throws, but I enjoyed watching the excellent rolling dice, blue for the player and red for the micro, which make first class use of the Spectrum graphics.