So, if the purpose of EA is to improve the game, but it is full price, it is unlikely to attract any but those that would have purchased the final product regardless of EA. You get something of an echo chamber effect, and are likely to get a more restricted range of feedback.
As this is not a means of gaining funding, one would not expect to receive access to the 1.0 release for anything less than the normal full price; but, an alternative might be a lesser EA price, which can be "upgraded" for the full game. I don't expect this to change, but there is some logic to it.
I am of the understanding, perhaps mistakenly (which would definitely change things if so) that we will not need to purchase 1.0 if we already paid for EA. If I am correct, then it is in Larian's best interest to list EA for the full price of $59.99, since as you said, a lot of people who would buy 1.0 will buy and play EA too, and would in effect end up getting the game for a cheaper price, thereby undercutting (perhaps severely) Larian's expected profits. For example, if they are hoping to have 1 million sales in the first year, that is 60 million in expected revenue. If 300k of those 1 million people bought the game via EA for $30, Larian would need to charge almost $73 for the remaining 700k people who buy 1.0 to make up the difference. If we will need to purchase 1.0 for another $59.99, then that is another matter entirely. We should get some official clarification on this.
