Is it ok to get euros from an atm in Venice airport?

You should be fine except most ATM's in Europe limit the amount you can withdraw. That is the only issue I see. We have used ATM's throughout Europe with no issues and very secure.

If possible, search out a bank affiliated ATM. Foreign Exchange firms own some but they give you an unfavorable exchange rate and might charge a fee above that. If you must use an FX owned machine, take out the minimum to cover the cost of your water taxi.

Courtesy of AI:
Avoid Euronet: quickvenice.com recommends avoiding private, non-bank ATMs like Euronet, which are common in the area and charge high fees.
"Bancomat" Brand: Look for the "Bancomat" sign to ensure you are using a legitimate Italian bank ATM.

No less safe than in the US. But you will likely pay extra for the convenience.

Use a no fees to open, use, fees rebated debit card at bank affiliated ATMs.

Yes, it is ok. But consider the following.

It is wise, in my opinion, to always have some euros in hand when you land because technology does not always work as it should. That is a simple fact of life. We have experienced a number of instances when credit or ATM cards did not work as they should for a variety of reasons.

You will be tired, jet lagged, sleepy, on new turf, and probably in awe of where you are. Most people (self included) don't need to be handling sharp instruments or operating an ATM under those circumstances. In addition, there is the problem of finding a "real bank" ATM, waiting in line to use it, and hoping all goes well. ATMs have been know to run our of currency at times.

The "extra" cost of getting 100-200 euros from your local bank before leaving in nothing compared to the overall cost of the trip. And it's a small price to pay to eliminate one more hassle upon arrival.

Regardless, be sure to check with your bank and or card provider to see if you need to place a travel alert on the ATM and / or debits cards. The same goes for any credit cards. Some require a travel alert, and others don't.

Enjoy Venice!

I've never used a water taxi in Venice, but I must say I'm very surprised cash is required. Surely some of the water taxi companies accept credit cards.