With the Switch, Nintendo is targeting games who typically play games on a smartphone, but have never felt comfortable with, or had the time for more conventional home console games before. The system was designed to make home console gaming more accessible to those gamers who up to that point, have only been familiar with apps like Angry Birds or Clash of Clans.
You're way off. Like, how do you look at Switch promo material and think "Yeah, this is clearly aimed at smartphone gamers"? Nothing in their current marketing approach suggests a direct attempt at upselling the system to the smartphone crowd.
The Switch's target audience is what you see in the ads; people who aren't adequately served by the established gaming platforms. If we ignore the Switch, someone who wants to play a video game on a current-gen device has two options; mobile and PC/PS4/XB1. Mobile games are (for the most part) simplistic and/or shallow, but extremely convenient. PC and traditional console games are elaborate and engrossing, but are a much more restrictive experience that requires commitment. It's just you and your PC/console, both tied to your monitor/TV for several hours. Moreover, with Wii sales falling off a cliff and Wii U being a disaster, console gaming moved away from local multiplayer, becoming a more solitary experience than it used to be.
With that in mind, the Switch's target audience likely includes;
1. People who would like to play console-quality games but don't want to commit to a stationary platform. People who game but no longer have the time to do so, mobile gamers interested in a meatier experience and the Japanese market all fall under this category.
2. Lapsed gamers. These are people who drifted away from gaming due to changing trends at some point before or during the 7th gen.
3. People who want to play games in a social setting. With two functional controllers in every box, Switch has the biggest focus on local multiplayer since the SNES.
4. Nintendo fans.
5. PC/PS/XB owners who are satisfied with their current machine, but still want the option to take their favorite games away from the monitor or TV.
Bethesda's ports appeal to 1 and 5, and could potentially sell to 2 and 4 as well.
Breath of the Wild for example, may seem like a daunting open world, but once you play it, it's actually a very simple game, as it only asks one thing from the player, just explore. Sure there's more to it if want to dig deep, but that simplicity, combined with it's pick-up-and-play short-burst sessions typical of mobile gaming is what makes it so appealing on a casual level. You can just run around chopping trees for half an hour if you want, and still have fun.
It's arguably the hardest Zelda since the NES games if you want to make any real progress.