To make something clear this is not viz doing this and is just a continuation of one of MD's core principles of increasing the visibility of freely available* official releases.
*Unfortunately region locking/licensing issues prevent some chapters from being accessable in some regions but that's nothing a VPN cannot over come.
Tbh, I would argue that allowing regionlocked or moneylocked materials of the official publishers to be put here is more of a detriment, rather than a boon to that mission.
As seen with the recent Kodansha site, an official publisher that takes over already popular manga series that were so far mostly drives away people who were actually already translating it and instead making it available to less people.
Honestly, as a reader, I kinda have grown to dislike most official publishers