You loose control over your members, and core features of your site are no longer accessible to them. Also, if you ever want to leave tapatalk, you loose all the members that came from tapatalk.
You still have their accounts. It's not backwards like you think it is. Basically, if you remove Tapatalk, you still have their accounts on your xenForo database. It's still there. Tapatalk is the one that will lose the most from this, because most of the content or the "accounts" are in their system, yes, but they really can't claim the content. They're just distributing your content on their system. I'll explain more later.
Not to mention tapatalk has a BIG history of a lot of exploits that they know about, but don't patch for a while. OR when they do patch it, they don't even inform the community of the exploit to let forum owners know to update and patch asap.
I've met with the developers of the actual Tapatalk team. They're nice people, and they do listen to your feedback. I was the one who brought the security issues to their attention from TWO different sides of the corporate ladder. One is the founder, and the other one is a sort-of a CTO. The exploits that were discovered were patched quickly, and even if they "left it alone," like you said, they investigated it throughly and tried to fix it so that it doesn't happen again.
They don't "inform" users or owners on the patch updates because it would mean, screwing with the older updates, leaving anyone lower than 3.x.x (for example), vulnerable. It's the same thing as wordpress, where if you left your wordpress alone for longer than a year, and they made a lot of updates, you're hacked. I've seen it before. Tapatalk probably wants to avoid that because they're more of an "external" mobile site.
By not using Tapatalk,
YOU lose benefits from
not using it. Already, there are hundreds of thousands of people who use Tapatalk, that has never seen your forum, or discovered your forum. Tapatalk is like Apple Apps or Android Apps that can be accessible from the 'start' screen. Why? Because underneath the app, it's actually a search engine of its own. So, if you're not on Tapatalk, you won't be able to access the mobile users that prefer "native" mobile viewing. xenForo can stretch the forum to your phone's width, but some people complain that it's hard to read on native forum view. Therefore, xenForo 2.0 would have to provide this "feel," to really push for more mobile viewing on forums. Otherwise, someone else will come in the forum world with a native mobile viewing. Right now, as it stands, that 'person' is Tapatalk.
On top of this, Tapatalk is the first "mobile" app to take advantage of Google's cuddling with mobile sites. It's the first company to be favored by the new Google system/algorithm where mobile sites are high on google's list to favor. Any site that does not have a mobile "site" per se, are "looked down" upon. Thus lower rankings. So, if you want your site to be seen by thousands of viewers worldwide. Tapatalk is your friend.
