It really doesn't. To understand why, you have only to comprehend the following: Whether someone is searching under a particular keyword, or just browsing whatever pops up on the home page, the average browser has a finite amount they're willing to scroll before abandoning their search... and chances are your video is NOT going to be placed highly in those results unless you're directing a firehose at it from offsite via Twitter, forum posts, news aggregators, or paying Youtube to promote your video flat out (which is such an obvious moneygrab on their part its disgusting). In other words: If you rely on their algorithm to promote your work you're literally playing the lottery and, much like the lottery, statistically you're going to lose. It makes far more sense to find bandwidth and hosting, negotiate with an ad network, and direct a firehose at the resulting site... but that's more work than some are willing to do. shrug Oh well.
If you place it on a website you’ll also be subjected to their algorithm, google search.
This is an amateurish take on marketing yourself on YouTube. The algorithm is /not/ like the lottery. My wife is a content creator on YT and hasn’t spent a dime on advertising. The free advertising isn’t in the form of search result placement (mostly) but rather the algorithm showing your videos next to more popular related videos. That’s why the absolute most important thing for video promotion isn’t the material itself, but rather the title/thumbnail combination. People are generally bad at understanding this and/or bad at marketing themselves so they attribute their lack of success as random chance
And unless your audience is very tech oriented, they’re not going to switch off whatever platform the ads are on to watch videos hosted elsewhere. You’d need to ask a LOT of people (= a large amount of $$$) and hope a few of them make it over a bit at a time