While there's nothing to fear from taxes, there is the completely separate issue of the benefits cliff [0]. When you just barely make enough to no longer qualify for SNAP or childcare and you lose 100% of those benefits instead of it phasing out based on your pay. This benefit is often worth more than a normal raise, so while you you don't take home less in your paycheck, you do have fewer resources overall. Phasing out benefits instead of making them all or nothing is a simple way to address this.

0 - theguardian.com/money/2014/jul/20/benefits-cliff-minimum-wage-increase-backfire-poverty