Yes, it says something about the agency that they're not prepared to meet you, and it's not good.
For 50%, I'd be expecting an incall location too, but things can vary. Work out what you'd actually be taking home, and ask 'Is that enough?'
Agency work is not safer: they have a vested interest in sending you to anyone with the money. This can include people who other workers refuse to see again - it's not the owners in the room. Do have a look here for a lot more reasons why agency work is not recommended, even though it does work for some.