I don't, paying extra for electronics that would be used once or twice and having a switch and batteries and a screw cover on the figure somewhere. Same for a tacky "beam effect" like they've been adding to Thor and SW, or mini Iron Men. I don't have a use for that stuff outside of maybe taking some photos with it once, and just getting it to make the figure seem like it has more to it is not very useful to me. This figure looks great, has a great HS and the costume looks the part, the cape looks exactly like the real design and frankly Vision's cape is thin and gossamer, I don't know what Hot Toys should have done differently. The wiring works pretty well to style it, that's more than Thor's does. I'm quite satisfied with mine, and I wasn't expecting to get more out of it than what was in the description.
Yeah, I don't need light up nonsense. Get someone to do the effect in Photoshop and it'll look a lot better anyway.
I didn't purchase the Vision figure but certainly don't understand why HT would release him without a light-up Mind Stone, but instead will release Ant-Man with light up features you can't easily see. I'm thinking it's related to the inability to hide the battery box since the HS doesn't lend itself to the task without a screw at the back of his head.
Didn't the sonar head that came with the Batman DX02 figure put the switch in the neck post (which was then hidden below the neckline when attached to the body)? I don't know why they couldn't have done something similar here.