[Aachen]

May work for small pages, like most of my webpages besides some downloadable files, but megabytes of JavaScript on an average (mobile?) connection are going to take very significantly longer to load, cost more battery, and take twice as much from your data bundle

Perhaps it's effective as bot deterrent when someone incurs, say, a ten times higher than median load (as measured in something like CPU time per hour or bandwidth per week or so). It will not prevent anyone from seeing your pages so information is still free, but it levels the playing field -- at least, for those with free inbound bandwidth dealing with bots that pay for outgoing bandwidth