If you are a hobbyist hosting your own website for fun, sure, whatever. Do what floats your boat, you're under no obligation for your website to meet any kind of standard.

The vast majority of web traffic is directed towards websites that are commercial in nature[1], though. Any drop in traffic is a drop in revenue. If you are paid tens or hundreds of thousands of dollars a year to provide a portal wherein people visit your employer's website and give them money (or indirectly give them money via advertisement impressions), and shrug your shoulders at the idea of 50% of visitors bouncing, you are not good at your job. But hey, at least you'd be in good company, because most web developers are like that, which is why the web is as awful to use as it is.

[1]The only website in the top 10 most visited that is not openly commercial is Wikipedia, but it still aggressively monetizes by shaking down its visitors for donations and earns around $200 million a year in revenue. They would certainly notice if 50% or even 10% of their visitors were bouncing too.