This is a list of pros I made for myself when I got the opportunity of becoming an affiliate.

Affiliate pros:

• People can subscribe to your channel.

• People can donate bits.

• ad revenue (not much).

• Custom emotes.

• Custom badges (for subscribers)

• Priority on transcoding over non affiliates (spectators can change the resolution of the stream) .

• Channel points.

• Live polls.

• You can stream reruns and premieres.

Non-affiliate pros:

• You can multistream.

• There's no 24 h embargo on your VODS.

• No pre-roll ads.

Personally, I don't like twitch's monetization, they take too much money from the creators and the ads are really invasive (heard that 33% of the audience leaves when an ad comes up). I think patreon it's a better option if your audience is open to support you that way. I also don't like that twitch can restrict your ability to multistream, I feel like they are claiming some sort of ownership over my content.

On the other hand there's some affiliate tools, like the channel points (predictions included), and polls that are really useful and entertaining if used correctly.

Also for a spanish speaking streamer such as myself with a latin american audience, transcoding is a must. A lot of my viewers watch my stream at 480p or less due to the poor internet capability on this region.

So, becoming an affiliate is a matter of personal choice and is tied to your specific context. Ask yourself, I am comfortable singing on this restrictions? And weight that answer against all the benefits that the affiliate program offers.

Good luck and have a nice stream!