It really doesnt work the same way anymore, especially as a money saving way to get from here to there and back. There was also a volunteering to get bumped part of flying that was even better.
I used to book either personal or business trips at the lowest fare. sometime i even selected them because of the layover city and time gap in the layover city or first flights out in the morning even though my business plans were next day. So you have a cheap ticket, not always a seat.
The standby part come in when you either want to take an earlier flight because you are at the airport or when at the airport and you have some buffer time, you volunteer to be on a bump list. If overbooked, they would offer passengers a voucher for a free upgrade or free flight if they waited for a later flight. If you get there early and ask to fly standby, if a seat is open, they would put you on the plane because its going anyway (often getting a first class seat or a nonstop), but saving money because that flight would have cost more.
There were also times when the layover city was a place I wanted to spend time in due to location of had friends there. So with a long layover, I would go visit and intentionaly miss my flight because I wanted to spend time in that location. When i wanted to get to my destination, I would go to the counter and give them a tale of why I missed my flight (politely of course because they didnt have to do it). Not once was I turned away from getting a seat that day.
I had many free vouchers, many nice stays with friends and family in mid layover cities.
Sadly, the industry and rules are completely changed and they don’t have to honor squat now.