This measure by the Chancellor seems ridiculous in a cost of living crisis. Loads of people working part time in lower paid roles are presumably doing so because they have caring/other responsibilities or ill health that means they can't do any more? So they won't be doing more work but will just have even less money. Great.
Kwasi Kwarteng to shrink part-time work benefits to grow labour supply
Further this seems a direct attack on women, and middle-aged women in particular as he is targetting over 50s. Obviously he wants women to do all the low-paid caring jobs that hardly anyone currently wants to do at the moment because there are other, far better jobs which pay more.
Adult social care in England is in crisis, say Tory council leaders
Another category of part time workers will not be receiving benefits but quite happy to stay part time as it suits their lifestyle/health needs/family needs. So again, they won't be going FT anytime soon and it will not increase the labour supply.