Teasing is a social thing. And like other social things the reasons are not necessarily concrete and "rational". Why do you smile and say hello to a person you pass in the hall? You don't intend to start a conversion- there's no reason to say hello. There's no "reason" to be friendly at all.

If you look at the social and emotional things happening, maybe it starts to make some sense. Smiling says, "Hi, I recognize you and you are an acquaintance/friend."

Teasing is a way of interacting- of making bonds, of feeling people out. By teasing, you are finding out about someone: How much do they care about the subject of teasing? What kind of person are they? And you are saying, "I know you so I can playfully poke at things you care about." And maybe eventually, "I know you so well, I can poke at you in a sensitive area but not go too far. We can do that to each other because we trust each other's intent and we know how to poke in a way that doesn't go too far." Strangers don't have that kind of bond and trust.

Besides that, teasing is joking. It can be simply harmless and funny and lightens the mood or improve the morale of a group.

So, yes, there are reasons.

I will never, ever defend anything like that in the workplace, but some people consider teasing and joking to relationship building.

There's no reason for a lot of human interactions that are ultimately good for a subgroup's social bonds.

I'd say it depends on a lot of factors such as local culture, company culture (or team culture for larger companies), etc. So just saying 'there is no point' is probably not an answer.

Humans do a lot of things that have "no reason".

I do think teasing, especially in cis male friendships, is very often a big piece of the bonding experience. It simply doesn't translate well to the work environment and should be left out.