How good are the token Allowance Tracker?

Hi guys. Some experience needed here please
TAC tool give me the possibility to check which defi has which privilege or pre authorization and also (and here you PRO help me) the possibility to revoke them. How? Connect to etherscan and bscscan in web3 (inside MM browser from mobile app) ?
I discovered that only Shiba swap has unlimited allowance, so what is the real danger here? modify the amount, limiting to my actual token value or completely delete the permission? Once done, the next time I use Shiba swap, it will ask again for permission?
I noticed that pancake swap, that I used often, has not such allowance at all, meaning that it’s asking permission every time it needs? So cake is safer than Shiba?