Is it bad to engine brake (tiptronic)?

[Perfectlap]

Assuming your taking about street driving, the real question is what's wrong with your brakes?

You have the privilege of having one of the best brakes in the world at your feets. Why would you avoid them and put more wear on one of the more expensive parts of your car?

In 15 years of existence and nearly 100K miles, my car has gone through exactly one set of rotors and brakes.
If you drive with your eyes, most of your braking can be reduced by simply lifting off the throttle rather than mashing the pedals.
Win win for brakes and transmission.
Your car has plenty of other mechanical weak spots, you don't need to create new ones.