Cost is not only a key consideration, but one that must be justified to management. The cost of externally produced programs is usually easier to calculate than internally produced programs. If external resources meet your needs, it's much faster to buy them than to make them yourself. Consultants can often do the tailoring for you, but they must often acquire extensive company-specific knowledge, and this adds more time. However, if knowledgeable internal resources are working on other projects, their time will need to be reallocated.
Quality is generally higher in programs offered by outside resources.
You don't need to buy a Mercedes when a Ford will do the job. Don't let technology mask content. Audience numbers and levels must be considered. If the number to be trained is small, a publicly offered seminar may be the way to go. If the audience is large and the training need will continue for a long time it may be more cost effective to build an in-house program.