That is a 240V breaker, not two singles handle-tied. You can tell by the labeling. They didn't bother labeling the other half.
Use of a 240V breaker is a perfectly legitimate substitute for a handle-tie.
One good reason
The usual reason to handle-tie two independent circuits is they both land on the same yoke. (A yoke is the frame of a switch or receptacle).
210.7 Multiple Branch Circuits. Where two or more branch circuits supply devices or equipment on the same yoke or mounting strap, a means to simultaneously disconnect the live/hot supply conductors shall (must) be provided at the point at which the branch circuits originate (the panel).
Removing this would be a Code violation and would place maintainers in danger. Normal procedure when de-energizing a device is to find a part that is energized, then turn off breakrs until it is not energized. That person is checking only one thing, not every wire on the yoke. That is normal.
The handle-tie is required to assure this method works. The handle-tie will assure the person turns off all circuits attached to the yoke. So they don't get nailed by a circuit they were unaware of.
This same rule also applies to multi-wire branch circuits (shared neutral).
Someone re-breakered this thing and did it wrong
There was never any suspicion of Crouse-Hinds breakers, so it's not clear why someone dropped $150 replacing all the breakers with the wrong thing.
The panel labeling plainly states it takes Murray MP breakers. Those are readily available, although it has been relabeled QP by Siemens.
The only BR family breakers allowed in thus panel are BRD (the pre-CTL tandems/quads, NOT to be confused with BD or BQ).
The only other Eaton breakers allowed in this panel are type CL. That authorization doesn't come from the label; it comes from UL Classification of CL as tested and approved for Crouse-Hinds. None of these are CL; I can make out where it says "Type BR / Type C".
All the breakers need to be replaced (again) with Murray MP, Siemens QP, or Eaton CL. If someone wants to "free up" some spaces or has an Eaton gift certificate to use up, they can also use Eaton BRD tandems and quads.
If the BRD option is taken, this may leave some empty spaces, with holes in the deadfront. You can't leave those open for curious fingers to find. The wrong BR breakers can be used as empty space fillers.