Keys are very important and the main problem it how to saev it,If any HOLD more than 100 BTC it is big threat for him or her to save for it.While the vaults and physical wallets improve the technology in other hand the Hckers ar using latest technology to reach the wallets.So Hardware wallets are more secure than the onlne,Care about your keys write down on papers and save papers in physiocal valults.