whether you like it or not, take home assignments just select for the people who can spend the most time on take home assignments.
Which means people like me who have a current job and a family and can't afford to spend several hours on a coding test to make sure they're above and beyond the competition either won't apply, or will send in results that will be much often worse than the competition because we actually only spent 30 minutes on it.
Unfortunately, majority of candidates are interested in the take home challenge over doing live coding session. And we optimize for the widest reach.
In regards of the results, I can't speak for others, but I write code for 26 years. What I look for is how the candidate thinks of the problem. Here is one of my favorite exercises [0]. I would obviously love to do this live but people get super nervous and stop thinking. I then have tendency to help them too much and learn much about them.
[0] >>39263923