It is being used. I have one at home (inet addr:44.143.24.52) Most of them are allocated for HAMNet (eg. the above). But some are also routed to the "real" Internet (eg. some EchoLink Proxies in that range)
TL>> mobile public IPv4 is quite rare these days. MV> Here all the mobile providers have stopped issuing public IPv4 MV> adresses years ago. I have a 3G dongle from KPN for my laptop and i MV> get a RFC1918 or RFC 9598 adress. No IPv6.
I *DO* have a dynamic IPv4 on my mobile. (Hitchison 3g) Most other companies use carrier grade NAT and private address space.