PS1 had the ability to play audio CDs besides playing games (another model could play video, can't remember which one though). PS2, sold as well as it did because it was a cheap DVD player. Wii attracted a market beyond gamers. DS and GB were cheap gateways for children into gaming and were very affordable devices which could be taken anywhere.
I can understand the difference between the Game Boy and DS. However, what you just typed makes it seem even more in line with the PS1 and PS2. A gaming machine that appeals to the core and casual gamer, that has additional multimedia functions (PS1 - CDs, PS2 - DVDs, PS4 - Bluray and streaming apps) as icing on the cake.
And a few points. When the PS1 launched, CDs had been around for 12 years. Absolutely no one was buying the $299 PS1 for its ability to play CDs. Players could be found for less than $50. The myth of the PS2 as a cheap DVD player needs to just stop. When the PS2 was launched for $299 in 2000, DVD players were available for ~$150, with some being $99 during the holiday season. By 2003, when the PS2 was $179, players were available for less than $50. Again, absolutely no one was buying it as a "cheap" DVD player.