In my opinion, PoW is the only reliable way, to avoid DDoS attacks. Scraping too much, too quickly is a light form of DDoS, although not intentional. PoW was invented in 2006 exactly for that purpose.
The genius of bitcoin (not BTC) is that it provides an organized and practical way, for PoW to be used by everyone on the planet. Some people find it strange, because there is an imaginary token created out of pure nothing which represents the PoW. It would work fine, without that imaginary token i.e. bitcoin, just by dollars of euros, but it wouldn't be internet native. The point is always to just send a minimal PoW with every http or tcp/ip request.
The genius of bitcoin (not BTC) is that it provides an organized and practical way, for PoW to be used by everyone on the planet. Some people find it strange, because there is an imaginary token created out of pure nothing which represents the PoW. It would work fine, without that imaginary token i.e. bitcoin, just by dollars of euros, but it wouldn't be internet native. The point is always to just send a minimal PoW with every http or tcp/ip request.