Does iPad 9.7 2019 have a different Touch ID?
There are two different generations of Touch ID hardware in Apple devices. The 2nd gen Touch ID hardware is widely regarded as being much faster — nearly instantaneous — compared to the 1st gen Touch ID. 

Regarding the specific Apple products in your question: the 2019 iPad uses 1st gen Touch ID and the MacBook and iPhone 7 both use 2nd gen. 

See this Wikipedia article on Touch ID for more details. 

As of this writing, the breakdown between products with 1st gen vs 2nd gen Touch ID is:


1st Gen


iPhone 5S
iPhone SE (1st generation)
iPhone 6
iPhone 6 Plus
iPad mini 3
iPad (2017)
iPad (2018)
iPad (2019)

2nd Gen


iPhone 6S
iPhone 6S Plus
iPhone 7
iPhone 7 Plus
iPhone 8
iPhone 8 Plus
iPhone SE (2nd generation)
iPad Pro 12.9-inch (1st generation)
iPad Pro 9.7-inch
iPad Pro 12.9-inch (2nd generation)
iPad Pro 10.5-inch
iPad Air 2
iPad Air (3rd generation)
iPad mini 4
iPad mini (5th generation)
MacBook Air (2018)
MacBook Pro