[shanusmagnus]

It makes a giant difference in the amount of time it takes to mine blocks, especially during hashrate fluctuations, where a currency without a responsive difficulty adjustment algorithm (e.g., Bitcoin) can be 'stranded' with a too-hard difficulty, which means transactions don't get processed, which means there's a giant lag in money movement and fee escalation, etc. etc.

The interplay between hashrate, difficulty, txs, fees, price, and sentiment is pretty complicated and definitely important. See http://www.fork.lol to see this illustrated.