Everybody copies everybody, LOL, but ATN copied Sightmark's Photon design from NV (Pulsar and Sightmark being partners here in the US) and that copied traditional daylight scope designs. Going with the more traditional rifle scope design appeals to a much wider audience. Not everybody in the US shoots a rifle with picatinny rails, but they can get 30mm scope rings regardless of the type of rifle/rings interface. In Europe, which is where Pulsar is based, right, picatinny rails are definitely not the main stream. So the ring system is a pretty smart move, befitting their primary European market and readily usable in their secondary American market.
I don't know any daylight hunters that want to use their rifle scope as their spotting scope. There are some good reasons for not doing so.