The 50% is up to a quickly reached limit in most cases.
They use the accounts to replace their potential retirement plan vulnerability. Once the cap is reached, further commitment to the plan becomes risky and foolish. The Roth is a better bet for most.
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Sure, I'm not recommending investing beyond the 3~6% of gross limit set by most companies.
But within that limit, it is hard to find a better investment. Above that make your own IRA or the like.