In general, it's 2020, and if every click on your site takes 5 seconds, something is very wrong.
Just look at its hover->click speed demo on the landing page. I'm getting 500ms+ if I click it casually like I do most links. All of that time could be spent loading the next page.
https://dev.to/ (blog platform) does prefetching to great effect.
The onus is on you to decide if this would create a bunch of false positive prefetches for your desktop users, like if your website was a bunch of densely packed links. You could also scope this to prefetch only a subset of links.
But your users deserve more deliberation over their UX than a kneejerk yay/nay.
Every page should load fast, obviously, but instantly means the data has to be prefetched and that's potentially a lot of data to download that the user might never actually need. That's a waste of everyone's bandwidth, especially on mobile. Pages that a user will view (eg first page behind a login), or that they're very likely to view (eg top result in a search), should be prefetched/prerendered but whether you should prefetch more than that requires thought and measurement.
Browser vendors should implement per-site traffic breakdown.
And if you read HN as much as I doing that could be gigabytes every day.
I think you mean "minutes".
Open the developer tools and prepare to be surprised how long the average site takes to get to the "everything loaded" state.
P.S. I'm only slightly exaggerating. There's an awful lot of bullshit being loaded behind the scenes on the average site. Good thing I'm not using a weak Internet connection.
> it's 2020
Hmmm... I actually have stopped worrying about bandwidth completely in 2020. My home and mobile connections have virtually unlimited data. I cannot finish them if I tried. It's amazing to see tech like this that leverages the excess data I have and converts that into speed.