Technically, it's Halichoeres lapillus. When Jack Randall described the species, he was initially thinking it was a Macropharyngodon as well. However, one of the key characteristics of that genus is the presence of pharyngeal teeth - which are in the throat. None of his lapillus specimens had them, so into Halichoeres it went. The official description paper has it as Halichoeres lapillus. It's still believed that it is an ancestral species to the Macropharyngodon genus.
It's an "expert only" for the same reasons that all Macropharyngodon wrasses are considered such, although this species is a bit easier than the genus norm.
I do have 4 of them...
But I don't necessarily agree with that.
I definitely wouldn't compare it to a choati - which is by far the most difficult Macropharyngodon.
The juvenile form of lapillus is very similar to M. pakoko, which would actually make it pretty similar to meleagris and geoffroy, genetically.
Being that lapillus has always found its way in limbo between the two genera, it's difficulty is also right there along with that. A bit more challenging than the average Halichoeres, but easier than the average Macropharyngodon.