As i understand this statement, its safe to use Portable Electrum on personal computer.
Am i right ?
So, assuming you have taken the proper precautions... ie. confirmed digital signature of Electrum portable download and have taken steps to ensure your "personal" computer is malware and virus free... then it should be perfectly fine.
The dangers associated with the portable version are that it can lead to "dangerous" or "risky" behaviour... ie. putting it all on a USB stick and then using that USB stick on computers that you have no control over. For instance, public computers, internet cafes, other people's machines etc. where you have no idea what is/isn't installed or running on them.