A safe place to store BTC is in bitBTC, which earns interest, by using metaexchange.info as an instant bridge. Keeping it on the bitshares decentralised exchange as bitBTC is the future, then people can trade it against bitUSD without hacking risk while getting exposure to the same market.
I hope these thieves are caught and the money returned.
Do you agree that it is more safe a personal wallet with multiSig (+ hardware wallet)? Or not ?
Nothing is safter than a cold wallet or hardware wallet. As for a personal wallet, that depends on the type of personal wallet, a light wallet is probably less secure but others may be just as secure or more secure with multisig.
But it's mainly about exchanges for trading. You can't trade BTC against USD or anything at all from the relative safety of a personal bitcoin wallet (yet), but you trade against the USD with bitBTC, because the exchange is in the wallet. bitBTC can be traded against bitUSD, bitGOLD, bitSILVER, etc. So for people who want to get exposure to the BTC/USD market, the bitBTC/bitUSD market is the most secure way to trade.