My opinion & architecture consideration: OH should aim at using local connectivity/APIs as much as possible, not only for performance reasons, but also for reliability (works even if adsl is down) and of course privacy reasons.
Cloud APIs such as “Legrand/Bticino with Netatmo” should be used for cloud2cloud integrations, for example towards Alexa/Google Home assistants or other integration frameworks like IFTTT.
For BTicino-OH integration:
- in case the BTicino gateway supports the local OpenWebNet protocol, this protocol should be preferred IMHO -> OpenWebNet binding (still work in progress… help needed!)
- OWN protocol is not supported in newer wireless systems like Living Now. Also, apparently these new systems do not offer local APIs (at least not documented). Luckily the network is ZigBee 3.0. There are examples of successful connections between ZigBee USB controllers like CC2531 (already supported by OH) and BTicino Living Now switches/plugs: see here. They say zigbee2mqtt module can talk to Living Now, and they use it to integrate with Home Assistant (I did not test it, as I have no Living Now items for the moment). This allows to avoid to buy or install the Living Now gw, because the gw roles could be provided by OH. This means that with some luck&experimentation the OH2 ZigBee binding could support these new devices too. Which means no code to develop and local control via ZigBee protocol: the best solution!
In conclusion, I am not saying that integration with BTicino cloud APIs is useless, in fact it’s the only option probably in the case of the Smarther Thermostat, and thus the reason for the excellent binding work by @Mr_Ronfo.
In other cases however local connection should be preferred when available.