I've been on both sides of the layoff conversation, and usually there are some loose ends relating to work-in-progress that can be tidied up with dignity if everyone has a couple days to do it. We're talking about reworking next week's client meeting, or sorting out some team/project responsibilities that ought to be handed off cleanly, or whatever.
Assuming that there's trust in both directions, too, it's decent to give laid-off employees a couple days to retrieve or delete personal information that's relevant to their life going forward. A work emailed picture of grandma's birthday party. That sort of thing.
The person you lay off today is likely to stay in the industry, and to mingle in the future with people that might be important to your future success. Take a moment to think how you want to manage that relationship. Tossing her/him out the door that day is one approach. But it carries a price.
A favorite example from finance. The guys who founded Kohlberg Kravis Roberts were thrown out of Bear Stearns quite summarily in 1976. They built quite a mighty firm in KKR and did not do a penny of business with Bear Stearns for many years.
KKR is still around and doing fine. Bear Stearns went bust in 2008. That single example isn't cause and effect. But it's a marker.