I went out and bought a 50' 220 RV cord and made two cords out of it - ones a regular 220 cord that's 45' long and the other is a short 5' one that is attached to my BendPak HD9 with a plug that can be plugged into the wall or my 45' extension - thus giving me the ability to operate my lift outside, as needed. This has worked out really great, with the long cord playing double duty. I now have a nice long extension cord for my welder and for the BendPak.
You might not think of ever wanting/needing to move your lift within your own garage or outside, but why limit your choices. You just never know what project you'll have in the future. Someday you might buy the caster kit and decide to move your lift outside for the added headroom, better weather, or you so you can pressure wash the underside of your project car or rider mower. Heck, you might even decide to build a new shop out back or simply move to a new place. Having a plug on your HD9 just turns it into a portable and more useful lift.