> LISAs are a trap if you want to buy in the South. You can only use it if the value of the property is £450k or less

In London it limits you. Outside of London, including most of the South, where the vast majority of British people live, most first houses cost less than £450k.

The limit should have been raised though yes. Or perhaps it should be set by region, I don't know. Hopefully it will be updated at some point.