It’s able to set up home automation rules for one sensor at a time, but the whole reason the ADT product was introduced is because the original hub is not able to do many of the other security related things. There’s no entrance/exit delay, there’s no cellular backup for contacting the monitoring center, the other sensors can’t be used for triggering ADT alerts, there’s no way to arm or disarm the system unless the Internet is available, and some other stuff.
Up until the ADT system was released The usual community recommendation was to get a separate purpose built security system and just use SmartThings for non-security purposes. In fact, the company’s own product usage guidelines say the same thing: don’t use the system for security or anything critical.
https://www.smartthings.com/guidelines
You can find lots of discussions in the forum about those issues.
The new nest security system has a really nice feature exactly for situations like yours, where there’s a button on each sensor that you can press to temporarily disable it. So it’s perfect for letting the dog out late at night. However, it doesn’t yet offer professional monitoring.
I’m not sure if Abode let’s you disarm an individual sensor or not, @SBDOBRESCU might know as he uses both that and SmartThings.
Simplisafe, another security system which is popular in the community, lets you disable an individual sensor but it’s like a 12 step process to do so and you have to do it from the main panel or from a laptop. So it’s OK if you want to disable it for a whole day or a week when you have guests or something, but it doesn’t really meet the dog walking requirement. In fact this is one of the reasons that nest, which just came out about a month ago, has the button on the individual sensors, a lot of people wanted that feature but not many systems had it. 
The professionally monitored security systems generally don’t like it because they think people will turn a sensor off and forget to turn it back on again and then blame the monitoring company if there’s an intrusion that doesn’t get reported.
Quite a few of the home automation systems, including smartthings, do allow control of individual sensors because that’s what you need if you want to do something like have a closet light come on when the closet door’s opened but you don’t want to have the light come on because the closet in another room was opened! You get much more precise control of the sensor triggers but then they aren’t as worried about what happens if you change the settings and forget to change them back.
The new ADT/SmartThings security panel addresses this by offering two kinds of sensors, one that can trigger calls to the ADT monitoring sensor but they cannot be turned off, and the original SmartThings sensors which can only be used for home automation not for calling the monitoring center. That solves the closet light issue, but not the dog walking issue.
Nest is taking a different approach by putting the button on each sensor and making it a temporary disable so it will turn itself back on automatically eventually.
More expensive home monitoring systems offer zone management where you can quickly turn zones on and off, but they just haven’t been offered in most of the low-cost security systems.
We will have to see if the nest approach is popular with consumers. If it is, I expect other systems may eventually add some variation of it, but it might take a year or two and require buying new sensors then. We’ll just have to see.