The way you describe using a tablet is the best you can do with a tablet, but it is far worse than using a chalkboard.
First, in providing the lecture notes you discourage students from taking their own notes, since they know that most of what they might have written will be provided. When a student is actively taking their own notes, they often add detail that help them understand their own notes later. Don't worry about whether or not student's "like the convenience of being able to look at their lectures outside of the classroom". Learning math isn't convenient. It's hard work. They need to be in class, taking good notes, following the lecture, and applying it to the homework problems. If they have to miss a lecture, they need be responsible for the material, and if they can't figure it out from the textbook they need to see you during your office hours, or a tutor. It's a system that's worked for a very long time, and the tablet changes it without providing any real gain, and in fact some loss. In the best of cases it promotes student laziness, and in the worst of cases it lends to students being even more lost than they might have been in a traditional class.
Second, because you are writing on something that is more like pen-and-paper, you will write faster. This makes it so that it is difficult for those of us who weren't discouraged from taking notes (in the first point) to keep up in recording our notes and at the same time follow what you are actually doing. It's always difficult, when you fully understand a mathematical concept, to force yourself to explain it slowly enough that someone who doesn't understand it yet can follow. The chalkboard imposes a bit of a speed restriction since it forces you to write everything in a larger space which takes longer.
Third, a typical classroom chalkboard provides more real estate, so if the student is taking notes and falls a bit behind (because they recorded more detail on a point, or decided to do a side calculation to ensure that they are following what you've done), it provides more of a buffer for them to use to catch up.
Finally, and maybe this one is just me, but there is a huge difference between using a cursor to point to something you've already written, and actually pointing at it on the chalkboard.
One other comment, not related to the tablet: The best math instructor I have ever had did the least lecture preparation: He looked at the book to see what subjects were covered in the sections he planned to go over before class, and then did not look at the book again. He then spent the class period explaining and proving the material as much to himself as to the rest of the class. The notes I took from his lectures were always more thorough and better explained than any text book I have ever read.
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