So where is Dash's malleability fix? If it's easy to do then why hasn't it been done already? Bitcoin, Litecoin, and Decred have Lightning in beta testing.
Those Google stats aren't specific to mobile. The article I linked explains why IPv6 is crucial to mobile networks.
"Why IPv6-only in mobile is likely to grow soon
Apple's new App Store IPv6-only support requirement is highly likely to enable acceleration of IPv6-only deployments in both the other US networks (such as T-Mobile), and may also unblock IPv6-only deployments in many mobile networks around the world.
IPv6 can perform better than IPv4 in mobile
The simpler network architecture for native IPv6 traffic in mobile networks (with fewer middle-boxes between the handset and the Internet) translates into better performance. In IPv6-only mobile networks (and in some types of dual-stacked mobile networks that transport IPv4 traffic in an IPv6 tunnel to a NAT44), IPv6 traffic has direct access to the Internet while IPv4 traffic has its access mediated through a NAT. These NATs add latency and can be bottlenecks as they can be expensive for ISPs to deploy enough capacity to keep up with demand."
Those NATs are a security hazard too. Do you want attackers to double spend using BGP attacks? Because only using IPv4 is how you let attackers double spend using BGP attacks.