Skipping Sight Stone can actually work
https://youtu.be/M6qtrAIyV5I?t=93
On Supports who scale with AP at least, it can be a viable strategy https://i.gyazo.com/cebe4f5759b1d6a120c59eb8fffa16cf.png
played with this dude(d1 sona main master last season) like 10 games in a row now in d1/master/challenger (hello match making), and we won almost all of them without him building sightstone
The reason to this is that because 5 control wards+trinket is enough for vision and because to get vision from a long distance you can get
, then control wards and trinket will provide vision on objectives+playing safe if you don't have vision is something that you do without realising it if you're clever
Then if the support has a high amount of AP, the utility/damage will be as high as your mid laner making you able to oneshot a target without the target to suspect it (like the ahri in the video)