Can I run PEX directly into my clothes washer?
Aside from the fact that I don’t think it would be allowed by code it would be inconvenient and if there was ever a problem with the mechanics inside your machine and water started spewing out all over your floor you wouldn’t have a way to shut it off or disconnected easily. 

Trying to save money now may cost you more money in the long run. 

Buy stainless steel braided hoses and if you’re still worried get an auto shut off water detection system. 

Do it right once or do it wrong once and then do it right the second time.