As long as we’re clarifying here, Roomie can use any of the iTach series of devices as they all have an open API. So can iRule. I am not a fan of Roomie’s ‘pay as you go, and keep paying’ pricing model, and prefer iRule.
And while iRule has no direct SmartThings integration, it is a simple thing to set up endpoints for the devices that can only be controlled by SmartThings (ZWave, etc.) so that they can then be controlled by iRule. For anything with an http based API (ala Philips Hue for example), iRule can control those directly.
It is only when you desire some level of computer control, or complex scenes involving multiple protocols, triggered from SmartThings events, that something like HAM Bridge is necessary.
Note that IIRC, even SmartThings can send the strings necessary via TCP to an iTach, so it is possible to build some gargantuan device type that would include all the commands you would want to execute for all your IR controlled gear. HAM Bridge just makes setting up and managing this stuff so much simpler. Plus it gives you the flexibility to call all of it from more places (Tasker, web browser, anything that can send an http ‘get’).