Yeah and in other chats sometimes, if they notice that you're a regular, mods will even gift you a sub on purpose so that you get a taste of subscribed experience and eventually, when that expires, you'll notice the difference between being noticed as a sub and ignored as a non-sub, so the whole idea is to get you to resub.
Other streamers shower you with attention when they notice that you're new and you're trying to get noticed in some other way (clips, jokes in chat, regular activity on the streamer's other platforms) and eventually start ignoring you when enough time has passed and you haven't escalated your level of dedication (money or other forms of free stuff).
Twitch is all about tearing down the mental barrier between your common sense and "I must give money to pretty girl".
Once you start donating, you're more likely to do it always, more often and in larger amounts.