Hi, Mesh co-author here. The point of the work was to save memory by “virtual compaction”; we hoped to be able to do this while not degrading performance too much, since compaction typically is quite costly. Our empirical results found that Mesh saves memory by between 16% to 39%, while imposing very modest slowdowns, e.g. 1% for Firefox (see Section 6 of the paper - https://people.cs.umass.edu/~mcgregor/papers/19-pldi.pdf).