No and Yes. A standard speakon does not allow you to plug a 1/4" plug in it.
Yes, there is a special
combo version that allows you to do this. Some manufacturers use this in their products.
There is a range of speakon connectors. The ones that are on amps are speakon audio connectors. There are video, lighting, data, and industrial speakon connectors.
The power connectors are nice. Like other speakons they lock in place. No more pulling out your power cord at the least opportune time.