Why pick a fancy coffin?

The deceased doesn't care.

Everybody else sees it for a few minutes before it's buried and (hopefully) never seen again.

So you say "it's respectful to the deceased". No it's not.

Showing respect to the deceased is taking the hundreds or thousands of dollars you would have spent on a coffin and putting it to a good use (s)he would have approved of - maybe making a donation to a charity (s)he supported, or if they died of an illness, to a hospital that researches or a hospice that helps support those with said illness.

Don't waste your money on a fancy box that you're just going to throw away.