Is it worth the additional cost to cast basement walls in place compared to building with lecablock?
Hardly. It's probably only when you are going to build a taller building that it occurs today. The exterior walls also get quite hopeless U-values.
I thought it would be sturdier as I intend to build a sutterängvilla. I had, of course, thought of installing platonmatta and two layers of cellplast, but that would have been done on lecan too. The alternative is prefab-sandwichelements. Difficult to find someone who sells to private individuals though.
Cast-in-place concrete basement walls in single-family homes have probably not been used since the 1940s. When using Leca blocks, their dimensions must be chosen with consideration to the wall's length, height, and location. Additionally, the amount of reinforcement in the joints is affected for the same reasons. There are excellent tables on this on the manufacturers' websites.