because it's fast and the people wants a "normal" e-currency with instant transactions.

This. It is literally that simple - people just want something that works well.
yes we all want something better that now,bitcoin have many problem on transaction or supply,or maybe price. but,have you think etherum will answer all bitcoin problem?or etherum just gonna be one of many crypto that have cheap price under bitcoin?
Because of the quick blocks, they arn't going to experience network congestion. Yesterday there was a period where just one bitcoin block was found in an hour, which increased the backlog. With Ether making blocks practically every minute it's not going to happen to them. And all the end user cares about is whether something works. They don't want to hear excuses or explanations about why their transaction hasn't gone through. They just want stuff to work.