Personally I would be against it because that kind of training is ineffective at meeting the needs of the company. It looks like an employee benefit which is nice but does it really gain anything for the company? It is like attendance at conferences, a nice benefit from the employee standoint but from a cost benefit standpoint, it often costs way more then the actual benefit to the company. Will these employee benefits help you retain people, unlikely but possible. Usually people leave for other reasons. Really if training in the cool new things is my priority, then not getting to use them at my current company after the training is going to be just as annoying to me.
What do you really need to do to train employees on the specifics they need for their jobs and then offer some training that expands them professionally. What you don't need to do is offer it to everyone willy-nilly. What you also don't need to do is have people take the training on their own time (very bad practice that is common). If training is important, it is important enough to be done during work hours.
It should also be focused not on what the employee wants to learn for fun but on what the company needs the person to learn to do his current job better or to progress to the next level. This requires a training plan where you decide with each employee what he needs and then provide it. Just handing out the key to a web site where they can get training is useless as the people who need the training on particular subjects the most will not be the ones taking advantage. The ones who do take advantage will be the ones who would be doing this training on their own anyway.
Instead of wasting money training the people who would learn on their own anyway on subjects which are irrelevant to their work or projected work, spend the money on improving the skills of your worst performers and giving specific training that might not be so job specific to high performers as a reward.
It is NOT your job as a company to give anybody any training they might desire. It is your job to determine what is needed and spend the money there.
Yes tech moves quickly and some training to keep up with new advances is needed. But it is better to do that as the company is getting ready to transistion to new things as well not just when someone feels the need. Training people on tech they can't use is counterproductive. Training people on something they will need in two years is just a waste of time as people forget what they don't use.
The most effective training I have seen is when you have employee-provided training on topics of interest. This serves your training needs well as the trainers have to learn about something and understand it enough to explain it to others. It improves the devs communication abilities which is also important.
The subjects can be scheduled to provide a mix of things the experts on your software need the less expert to get trained on and things that expand everyone professionally. It also means that you consider training important enough to expend time during the work day to provide it. It means you have some control in insisting that your lesser performers expand their horizons whether they wanted to take the intiatiatve to do the training on their time or not. It also allows people who would like to expand ther horizons but who do not have the personal time available (like young mothers or people caring for a sick relative) to do so on their own time.
This approach allows you to balance between training we would like to have, training we all need for a change in how we do business, training to help people be ready to move to new respopnsibilites, and training that some people need to be able to do their current job. It is much more effective than abdicating your responsibilty by setting up a system where you don't have to think about what the real needs are.