It's not designed with the safety of the user in mind. It's designed for the strength and stability of the Steem economy. Among many things, it protects against actions such as pump and dump and other similar fraudulent strategies. If you want details on the specific thoughts that went into this decision, check out the Steem Whitepaper, specifically the Steem Power section.

The essence is captured in the first three paragraphs, so I will quote them below:

Start up companies require long-term capital commitment. Those who invest their money in a startup expect to wait years before they can sell their shares and realize their profits. Without long-term commitment, a startup seeking to raise additional capital through the sale of additional shares would be competing with existing shareholders looking to exit. Savvy investors want their capital contributions to grow the company, but growth cannot happen if the new capital is given away to those looking to exit.

There is significant value to having long-term commitment because it enables communities to make long-term plans. Long term commitment of stakeholders also causes them to vote for long-term growth rather than short-term pumps.

In the cryptocurrency space, speculators jump from cryptocurrency to cryptocurrency based mostly on which one is expected to have short-term growth. Steem wants to build a community that is mostly owned and entirely controlled by those with a long-term perspective.