The datasheet from the sparkfun page doesn't make it look like this particular chip would be all that useful. The performance data indicate a max of 2mm error from noise and max 13mm range offset error. Operating at 2.5-3V, and interfacing with I2C would also add additional costs and programming time as I don't think any of the electronics support using I2C for positional feedback. The chip alone is $3+ if bought in bulk, and I don't think that's getting you anything additional than you can already get from multiple other methods cheaper. I think the intended purpose of the IC is for detecting movement and gestures in a broad manner, not precise positioning which is what printers would need.
