Meierme
Well if you want $10 a month off, feel free to reach out for a code via the SimpleX link in my profile.
gMan
IMEI is tied to the hardware of your phone. IMSI is tied to your SIM card.
Switching IMSI makes it harder to track you and harder to associate you with the data, but not impossible. If law enforcement has your IMEI number and is willing to put in the effort to track you with it then they can do so.
Ultimately Cape is about protecting yourself against entities that aren't US law enforcement. While it would make their job harder than any of the other carriers, it won't protect against them.
pixelfairy
That calling it an outright scam is a bit much but its really close. Its basically Mint Mobile but you can pay with crypto (note that you can pay for Mint with a prepaid visa gift card) and they don't directly sell all your data (T-Mobile, who has like 99% of that data still sells it all though).