I would disagree, closed emitters have only in the last few years become more common and up until the EPS came out there weren’t any micro enclosed dots. I have been CCing a pistol with a dot for at least the last 7yrs. My dot has been unusable due to lint precisely zero times. Is it possible? Sure, but not likely.
For duty use I would be more inclined to go with a closed dot but again, RDS usage in Mil/LE has become extremely prolific and most are still using open dots to include our Tier 1 units. If it’s an option and in the budget sure, go for the enclosed but nothing wrong with the open emitter style optics.