Wondering if having both would slow down the system. My thoughts were that with a HOSTS file incorporated in uBlock Origin, it is one less thing to update. What do others think?
I think there are some similarities between using the Hosts file and the block-lists used by browser-based ad blockers to block content. Some people use both ...
The HOSTS file approach uses no memory or processing power, and blocks across the entire OS (not just the browser). DNS resolutions are very quick, but the trade-off is that you can't block individual elements (only entire domains) and per-site customization can be difficult. There is also the issue of how often the HOSTS file is updated and the manual installation.
The ad-blocker incorporation approach makes it easier to enable/disable on a per-site basis, but the trade-off is higher memory or processing usage, and you are only blocking things within the browser.
I suppose some decision factors would be how paranoid one is, and what kind of safe computing habits one practices.