People buy dedicated readers for various reasons. Some people don't like interruptions while reading, while others are easily distractible. Dedicated eink readers add other reasons. Even heavy readers only need to recharge their device once a week and it is easy to read outdoors. Other people will add other reasons to that list.

At the end of the day, the decision is not a no brainer because it depends upon a person's needs and wants. Some people will want a dedicated reader, others will want a tablet. In some cases, it will even mean that people will buy both and use the ereader and tablet in different circumstances.