Can the jailbreak cause permanent damage to an iPad

Yes, is theoretically possible to permanently damage a jailbroken device.

For example, you can permanently disable Cellular features if you load incorrect Baseband firmware - something which is possible, when jailbroken, as normal safeguards have been removed or disabled.

Remember also that Apple will decline service/support/repair of any device which suggests or shows evidence of having been jailbroken.

Caveat Emptor - if you jailbreak, you’re on your own if/when you break your device - with no comeback to Apple.

Seems most people try jailbreaking for two reasons.

One is to tweak system settings in ways not supported by iOS. But, when you do that you may well introduce instability, causing your device to crash a lot, churn through a battery charge faster or other unforeseen consequences.

People also want to download and install apps not in the App Store (many specifically denied by Apple). But, again, you have no way of knowing what else is bundled into those app’s installers and you’re basically granting them root access to a completely wide open OS and file system when you install them. If you wish to be compromised by everything from malware to key loggers and spyware then by all means go ahead (the truly malicious software makers are drooling over people who do that sort of thing).

Also note that updating the operating system will require re-jailbreaking it, as every iOS update will break the jailbreak. And it may be sometime before anyone jailbreaks a new iOS release, leaving you stuck. And, as already mentioned, yes, it is possible to do things that will render your device “bricked” in the very literal or true sense of that term - you’ll then own a thin glass, plastic and metal brick, not even thick enough to be suitable as a decent doorstop.

And jailbreaking also breaks your ability to get service and support from Apple. It's simply not worth the risk of:

A: Taking a chance of bricking your device - Then

B. Not having access to Apple Support if you do - And

C. We won't be able to help you either

Probably not. However, while your device is jailbroken, your data may be at risk. It's just not a good idea.