Hi,
regarding sending email after interaction (interaction record saved) this could only one of these to be used.
There is also another way - to use workflow - to assign it to event after save. Just trace for event triggered in SWEL.
hard to say which one is "easier" - each of those works in a completely different way, and has its pros and cons. I believe for sbd new in CRM without deep knowledge of WebUI and configuration, I would go into CRM Events (one tcode to make config and assign own function module) or workflow.
Workflow will also do it asynchronously which might be a good idea here.
BR
Radek