July 2018 NPD: Switch #1, Octopath Traveller #1 software, UPDATE

[Nautilus]

LGBTDBZBBQ said:
According to Benji(market (insider) Pokemon Let's Go interest is lower than other previous mainline title and has 0 effects on Switch sales currently, while Super Smash Bros Ultimate is the opposite in comparison since E3 Direct with a huge interest from new buyers.

As it has already been said, Lets Go will have little impact as fara as the core fans are regarded.Where it might and most likely will cause an impact is with casual fans, those who play Pokemon occasionally and specially those who have played the originals.But that effect will only start being felt when Nintendo go all in with marketing(read it as having ads on TV and such)