If you can afford to get the automation installed with the pool then do it then. It will be simpler, cleaner, and probably cost less then retrofitting it in later. Like I described above, most automation panels integrate the electric load center/sub panel. Automation ties into the electrical to control the devices.
It becomes more complex to tie into existing electrical work. And complexity gives more points of failure and lowers reliability. A tech geek may enjoy continuously working on the complex automation they create. Many folks just want automation to be an appliance that works reliably.
A heater can easily be installed later if properly provisioned for. The electrical for it available at the equipment pad, the space for it on the equipment pad, and the plumbing run so the heater can be connected between the filter and chlorinator/SWG.