What do you mean with "they don't depress the tongue"?

I see your point, but let's not lose our sense of proportion. How much pressure are we really exerting inward on our dental arches when we suck on a straw for a few seconds? How does this compare to a few seconds of tongue chewing, or a good strong postural suction hold?

I'd certainly rather use a straw for acidic beverages, to minimize their contact with dental enamel. 

Also, you can still do a proper tongue swallow after sucking liquid into your mouth from a straw.

@darkindigo How does it stop a good swallow? You just bring the liquid into your mouth, and then swallow.

If you're breaking the swallowing pattern of your life already, I don't see how a straw is an obstacle. Mike Mew even talks about how pausing before every swallow is a good habit to get into. To enforce the new pattern.