What i mean was like, i have bought a copies of One piece, but i have to use some apps to read that, while i have bought it with a full priced. For example i bought a manga online on some random online bookstore. The price for the digital version of that manga cost about $7, for the physical version it cost $10.
It's understandable/acceptable for the price, with $3 different, because probably it was a cut-off from the printed cost which is come from the printed version, the digital version is print-less..., But why do i have to read manga on some apps that were used for read manga online ? Why can they just give us, customers, the pdf version of the manga ?