You can use it for a few minutes like checking messages or emails. Definitely no calls when charging. Playing games are okay if it's a AC room or with a clip-on cooling fan.
Yeah. It would definitely impact the hardware of the phones. Sometimes, it might cause serious problem too. It's better to use your phone when you have charge.
Its better not to use phone while charging, because while using the phone the battery heats, continuously using in that manner lead to battery electrolyte damage and eventually lead to battery failure within years
Normally it heats up while charging n using simultaneously, if your phone doesn't have good cooling performance then using while charging is not recommended. 👍🏼
