These are my thoughts:
1) Faster table turn times (and why they don't matter) - Yes, faster table turn times will occur with the tablets on the table because people can pay much more quickly when they are done with their meal. The big problem that people forget about is 90% of the time restaurants are not interested in faster table turn times. They need more people in the establishment. When was the last time you went to Applebees and they were slammed with people and had a huge wait? Odd's are that it doesn't occur that often.
2) People Dine out to be treated (waited on hand and foot) - Usually when you have made a conscious decision to dine out, you are doing so for the experience. When you decide to dine at your favorite restaurant, part of the experience is being waited on hand and foot by someone else. If these tablets start to replace people, it will certainly hurt the experience of being waited on. You are now going out for food, and not the experience. When people are looking strictly for food, we have seen that they tend to go to fast-casual restaurants (Chipotle, Potbellys, Noodles & Co. Etc.).
3) Menu on tablet (Higher App sales + lower costs) - This to me is a large long-term benefit for the restaurant. They can really create some powerful images for their menu items, which is correlated with higher sales. Also, you have eliminated the costs of printing menus every time you have a change.
Overall Impressions: This is a company that has created a product for an interesting niche. I don't ever see fine dining establishments using this because it detracts from the experience (#2). It does effect table turn time, but the large majority of restaurants wish they had table turn time issues, most are looking for customers (see initial success of groupon in restaurants). The Applebee's of the world are fighting hard with the fast-casual establishments and almost seem like they are in a race to the bottom.
I also don't see independent restaurant owners ever using a product like this because it has 1) high implementation costs (time/effort/cash) and 2) has some effect on sales but not because of the ordering platform, only because it has allowed me to create essentially a moving slideshow for a menu that entices customers while they are at the restaurant.
In my opinion, the person/business that successfully implements tablets in a restaurant will do these two things very well. 1) Allows servers to use tablets to take orders (lowers restaurants costs) - This will essentially allow a restaurant owner to decrease the amount of people on staff, yet still maintain high quality experience for guests, because a server that does not have to walk back to the POS system can handle more tables.
2) Creates a tablet menu that entices guests to order more items - The appeal of tablets on the table is the fact that people will be more enticed to order apps/desserts because of the power of high-quality enticing pictures. This has already been done by plenty of companies, but no one company has dominated.