On my bolt, there wasn't a lot of heat on it with the hotspot enabled, except when charging and the screen on for other usage. I typically turn the hotspot on, plug it into the USB port on my laptop, and use the USB for charging, with the screen off. But if I'm actively using the phone at the same time, it does tend to get warm. As for drawbacks:
If you aren't on the unlimited data, then you will have the cap to worry about, although based on what you claim your habits are, maybe not a problem anyway.
You'll need to keep your phone near a charger more often than not, depending on how long you are staying online and connected.
You will be eliminating internet for the house whenever you go somewhere with your phone. If someone is left home, they will have nothing when you leave.
Also, and this doesn't sound like it would apply to you, but if you had any devices without wifi capability, you would need either an adapter for it, or you would need to create network bridges etc to hook into a wired home network.
LG G2 (VZW) - CleanROM 1.0 | Samsung Galaxy Nexus LTE - Stock
Asus Nexus 7 Tablet - Stock
Retired: Motorola Droid 3, HTC Thunderbolt, Samsung Fascinate, Samsung Omnia