I often use IReadOnlyList<double> for arrays of doubles (or other value types) to indicate that sure data is not to be modified:

class X {
public void ProcessSomePreviouslyCalculatedResults(IReadOnlyList<double> data) {
 // do something with data
}

I know that there is ImmutableArray<T>, which guarantees that the content cannot be modified (unlike IReadOnlyList<double> which could be casted to double[]) but introduces another level of indirection. I wonder if ReadOnlyMemory<T> would be a better choice. In the documentation and the guidelines the motivation for using (ReadOnly)Memory<T> is always the replacement for (ReadOnly)Span<T> at places where the latter cannot be used.

Are there any drawbacks for using ReadOnlyMemory<T> at places where I want to pass a readonly array around?

One thing I notice is that one has to use

 MemoryMarshal.ToEnumerable(readOnlyMemoryInstance).Select(...)

instead of

 ireadOnlyListInstance.Select(...)