One reason I tend to buy my back issues as single issues rather than as trade paperbacks or those big volumes is for the advertisements and letters pages.
Especially with comics from before my time, it really helps put me in the mindset of readers from the era. Especially the back and forth dialog between the letter writers and editorial staff.
I can’t see any good reason why the letters pages would not be included with digital copies of old issues of comics.
I was really hoping a subscription service like this would mean I could stop the steady multiplication of longboxes taking over my basement. But, I really want those letters columns!