Yes, me! I have the Elk WSV (which I spent a lot less than $500 for, maybe $350 at most. It shuts off 30 minutes after armed away. It has been doing this for 2 years now. The pipes stay presurized so I don't think there is any risk of water hammer damage effect. Furthermore, I have water hammer arrestors and lastly the valve turns on gradual enough that it doesn't slam the pipes.
The 30 minute delay gives enough time for the laundry or dish washer to finish. This assumes that it was started at least 20 minutes before leaving. Every once in a while my wife starts it and leaves right away which causes an error on the appliance.
I wouldn't get a pvc valve. It might be cheaper but the pvc ball valve on my sprinkler system failed in 1 year with virually no use. Stick with stainless or brass. This is something you want to install and never worry about again.
Oops. I forgot about dishwasher/washing machine.. My dishwasher can run for up to 3 hours and the clothes washer can take about 1.5 to 2 hours. That would hurt WAF if she came back and nether was finished. So, I would have to set my turnoff timer to be over 3 hours after start - better than nothing I suppose.
Or of course, monitor if they are on....