@Kha It has a few advantages over `<or>` (`<|>`).
- It is not an infix operator.
- It takes tactic sequences instead of tactics as arguments
For example, we can write
```
first
| apply h1; assumption
| exact y; exact h3; assumption
```
or
```
first apply h1; assumption | exact y; exact h3; assumption
```
instead of
```
(apply h1; assumption) <|> (exact y; exact h3; assumption)
```
