Using it as an Alexa "front end" to replace HA Bridge, yes, absolutely. That's how I use it with my Stargate. Rather than recreate all my 'events' in the Smartenit P2, I use it to trigger actions in the Stargate rather than control anything directly although I certainly could. This method is particularly useful if the event in the existing controller contains X10 extended codes. Here's an example using just simple language:
Event Name: Office Lamps
IF time is sunset -20min
THEN
A-1 ON
A-2 dim to 50%
A-3 dim to 44% (extended code)
ASCII OUT COM3: close shutters
In the Smartenit, I defined an X10 address, N1, as 'Office Lamps' and use it as a trigger by adding one line to the above event:
IF time is sunset -20min
OR N1-On is receivedTHEN
A-1 ON
A-2 dim to 50%
A-3 dim to 44% (extended code)
ASCII OUT COM3: close shades
So now when I tell Alexa to "turn on office lamps" the Smartenit sends N1-On, the Stargate hears it and runs the event. No reason you couldn't do the same with Home Genie, Ocelot, or even the CM-15a. Of course, if the event only controlled one X10 address you could just have Smartenit control it directly.
My Stargate also has a serial connection to the Caddx alarm panel so when I tell Alexa to "turn on alarm" it sends N12-On which triggers the Stargate to arm the alarm.
If you order one, the Harmony P2 is $39.99 and the X10/Insteon PLM option adds $20. In addition to X10 & Insteon, it also has ZigBee built it. It has an Alexa Skill, Android & IOS apps and web portal access.
https://smartenit.com/product/harmony-p2/