The freebie Centech multimeter can measure mains, or more. The likelihood of a consumer experiencing an issue that would cause the meter to explode or injure its user is low, and it depends at what CAT level measurement is made.
But because DMM are used as general purpose tools to examine many types of faults, you never know when the critical fault will occur that it has no protection for. For example, if used by a professional electrician, the types of exposure are wider and riskier.
Toronto Ontario relatively recently [ compared to OSHA and the US] banned use of NRTL unlisted meters for professional contractor work. Certified meters have all the protection built in. Their pre-ruling stats are in this promotional brochure, they say they had 26 reported DMM accidents in 8 years, and that is for all licensed contractors in Toronto. Last I heard accident rates are down >>90% and are posted on their website.
The lesson is you can get away with it, but the accidents happen they are wholly preventable with a better meter.
I've used cheapos myself for 30+ years off on when didn't have my own DMM and had them fail less than a handful of times, and only 2x they smoked and died [ this is all back in the low tech setting of the Marianas. ] They're more likely to drift off over time mostly from age or abuse. But with my personal Fluke its never happened in the same period, 30 + years and I try to bring it everywhere it might be used to avoid such issues. Its cheaper than seeing a doctor, even if rare, and so far, I can only die once.