@Suiseiseki modern JS frameworks and libraries, such as React and Angular, implement various optimizations to reduce the number of requests; web sockets and pipelining then minimize the number of connections. Local processing can be also less risky.
Pure FastCGI apps will almost always waste more bandwidth, requests and computational power.
IP analysis can't detect modern scrapers and AI , so PoW is always used along with machine learning or behavioral analysis.
CC: @tennoseremel @quasi @lxo