I sometimes bump into something an Alexa Skill can do, that Home Assistant can’t yet do. The Home Assistant Cloud integration is great at revealing Home Assistant entities to Alexa, but as far as I can see it can’t speak to or call Alexa specific features.
For example I have the “Somfy TaHoma & Connexoon” Alexa Skill, which provides blind position “scenes” to Alexa which I’d like to call from Home Assistant. I currently have an Alexa Routine which calls the scene, but I can’t trigger either from outside Alexa.
There currently doesn’t seem to be any service to trigger Alexa skills, routines or scenes. There’s a few workarounds such as using a 3rd party service to “speak” to Alexa, or the alexa_media_player component which has support for calling scenes, but this component seems mainly for turning Alexa devices in to media players.
Adding Home Assistant services that can call Alexa skills, routines or scenes seems like a useful addition to the core Alexa integration gain access to features that may only be available from within Alexa.