Tourists stay in cheap hotels with children too! And they do this all the time! All tourists want their kids to be safe unless the parents are idiots.
What you get with a more expensive hotel, like your suggestions, is fancier trimming, work out rooms, pools, saunas, etc. Nicer looking lobby. Tourists with less money for hotels also value their children too but those hotels stick to the basics more - like beds, toilet/showers in room, A/C, TV and towels and linen. Most hotels charge extra for a bed for the kid.
Both hotels are in good locations.
Tourists with children even stay in hotels under 1000 baht a night too.
If your kid doesn't listen and likes to run off all the time maybe use a harness when outside. If he is out of control he is more likely to be squashed by a bus or truck than having a problem in a cheaper hotel.
You have to keep your eye on your kid in a fancy hotel just as much as tourists staying in cheaper places.