They have two disadvantages:
- they donīt break laminated glass
- due to the small size theyīre hard to handle when youīre really nervous

If thatīs not an issue for you, they may be usefull. Iīm not sure about the keyring but with the options from the other pictures, you probably canīt reach it when you need it.
I prefer the bigger tools.
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If it isnīt broken, it doesnīt have enough features yet.