If someone is known to have a high level of knowledge on or experience with a topic, then giving weight to that person's opinions on the topic is not a bad thing to do.
(also, I'm tempted to label comments like yours "argument from informal fallacy" -- you've offered no actual critique of any actual arguments, you've just named an informal fallacy, apparently in hope that people will take that in itself as an argument)
(also, I'm tempted to label comments like yours "argument from informal fallacy" -- you've offered no actual critique of any actual arguments, you've just named an informal fallacy, apparently in hope that people will take that in itself as an argument)