Why? People generally seem to like their time zones broken into an hour or less.

I live in Europe and it's very convenient that all of it fits in 3 time zones.

There's also an initiative to remove DST. If not for Covid, Europe would've already cancelled DST.

Australia is bigger than Europe. Time zones are about changing the clock time to match the sun time as you move across the earth. Moving farther means you have to change it more to keep them in sync: therefore, more time zones.

Australia and Europe are about the same size.

Exactly matching the sun day is not very important. It's more useful to have your time zones match your neighboring countries so that more people shared the same time.

No - east-west Australia stretches further than eastern Ireland to western Ukraine. And that’s an opinion, not a fact. Time zones are just a way of estimating when people in a location will be around and having a way to communicate who you’re using as a reference. You’re free to use UTC today, if you want to - but it’s not generally useful if you also have to manually map out “x is in England so he would be at lunch 2 hours earlier than me, but y is in Belarus so after my 4pm he will be leaving work for the day”