3G gives PS Vita "immediacy", Sony has said.
The more expensive Wi-Fi plus 3G model of the recently launched handheld provides the "true" Vita experience, SCE Worldwide Studios Europe senior vice president Michael Denny told Eurogamer.
Vita's 3G service, powered by Vodafone in the UK, lets you use many of the console's features without the need for a Wi-Fi connection.
These include social networking apps, such as Facebook and Twitter, and the likes of Near, which lets you connect with other Vita gamers out and about.
"PS Vita is a connected device at its heart," Denny replied when we asked him why Sony made a 3G model in the first place.
"You only get the true experience of a lot of what PS Vita has to offer in terms of some of the games and some of the applications we have, such as Near, when you're connected.
"Now, we can have all those features on Wi-Fi and they work perfectly well, but if you've got 3G it's always on. It gives the device immediacy.
"And there are a lot of people who want to have a system that's always on, so they can have that experience any time, that if they've got a location-based game, they know with the 3G network they can experience that 24/7."
The Wi-Fi only model is sold for around Ł230 and the Wi-Fi plus 3G model goes for about Ł280, although many retailers have aggressive offers.
Worldwide Studios chief Shuhei Yoshida has said 3G is something of an "experiment" for Sony, describing it as "our investment in the future".
Denny told Eurogamer Sony was keen to offer gamers a choice. "It depends on what people want from the device and how they consume things," he said. "But it's right from our perspective to offer that choice to consumers."
Vita is designed to offer the most powerful handheld gaming experience around - and comes packed with over half a gigabyte of RAM and impressive graphics technology.
Many of the launch titles from Sony-owned developers are designed to show off what Vita can do in terms of graphics - Uncharted being perhaps the best example.
According to Denny, though, this is just the beginning. He promised fans that Vita games will get better throughout the console's intended long lifecycle.
"We're really proud of the launch line-up for Vita," he said. "Not just the quantity - we've announced 50 games - but the quality of those games, but graphically. It is like a PlayStation 3 experience in your hand without compromise.
"But of course they will get better. Developers will get more out of this system."