Is SEO best way to get traffic?

Hi guys,
I believe that this depend. For example for dropshipping store which sell salami pattern socks better option will be paid traffic from Instagram or Facebook ads.
But what if website is something like movie streaming?
I mean if you upload video to youtube with trailer and put link to full movie in description you will get tons of traffic with less effort then SEO but the most important part is time. You can get traffic same day you post a video.
Do you think I'm right with that kind of mindset?
And i know that sticking to one source of traffic isn't good idea but if you are starting and you don't know anything about SEO better option will be focusing on other sources of traffic and later outsource SEO.

yes ur right. if you wanna instant traffic you must use social media. but you wanna lifetime traffic you must do SEO.

If you are not good at buying traffic, then yes. If you dont know any other way to get traffic.