A field guide doesn't tell you what you are looking at. It makes you look at details, interpret them in conjunction with the guide and learn simultaneously the features and how to interpret birds in different conditions with field guide data.
This device just gives you an answer. No learning. No details. No remembering. Dependence on the device, just like all the people that no longer know their friends' phone numbers, or drive into rivers/railway lines due to duff satnavs.
This thing will substitute for learning for most people. Ability will decrease.
Edit: Here's a thought. We've already seen the committees reject a putative first for Britain due to no photo. How long before they start asking what Merlin makes of the photo? Alternatively, with the availability of Merlin, what need for committees?
John
