There is no way on earth that Bitcoin could possibly scale to being a general utility. At 1 megabyte per block, the blockchain can only do a maximum of 7 transactions per second, worldwide total. Typical throughput in early 2017 was 2 to 4 TPS.
Compare with the systems Bitcoin claims it can replace: PayPal, which ran about 115 TPS by late 2014; Visa, whose 2015 capacity was 56,000 TPS; even Western Union alone averaged 29 TPS in 2013.
Various off-chain workarounds have been proposed (sidechains, Lightning Network); advocates talk about these as if they already exist, rather than being stuck in development hell.
Advocates sometimes excuse the electricity wasted on mining by claiming that it’s nothing compared to the energy used by the conventional banking system; this is simply false, with Bitcoin mining taking thousands of times the energy per transaction.
