Safety considerations:
1. Can you guarantee that during an attack you will always have a free hand available to rack the slide?
2. Can you guarantee that during an attack, the criminal will give you enough time to rack the slide?
3. Where would you rather load your gun...in the relative safety behind locked doors where you can carefully and deliberately insert a magazine, ensure that it is seated fully and securely, pull the slide fully to the rear and ensure the slide is all the way to the rear, observe the chamber when you release the slide for indications of a malfunction, verify by whatever means you choose that the round is fully chambered, and then top off the magazine with one additional round if you choose to.... or would you rather be loading your gun with the criminal pressing you with their own weapon and hope that it loads properly the first time, because you probably won't get a second chance at it?
4. If the gun suffers a malfunction during loading, where would you rather have that malfunction occur... behind locked doors where you can investigate the cause of the malfunction, properly clear it, correct the deficiency, and reload the gun verifying that it loaded properly the second time... or have the malfunction occur when the criminal is pressing you with their own weapon?
5. If you carry your gun with a round chambered, during routine gun handling there is less likely chance of you being complacent and assuming the gun is unloaded causing a negligent discharge.
6. Don't pull the trigger - the gun will not go bang by itself unless it is really broken.
I have always carried with a round chambered. When I became confident, I started carrying with the manual safety off. When I practice, I still make the motion of sweeping the safety off in case it accidentally gets activated - but, in the heat of the moment, if I forget to sweep the safety off it should not be on anyway and the gun should go bang when I pull the trigger.