In context of this topic, that kind of "ODAPI" would be used to 'pinpoint' the CTB, and guide for the most of the way - near the helipad where the guide path have increased error, there would be enough reference points to make a safe touchdown without looking at the device. On aircraft carriers the "meatball" is also useles when over the deck.
The LEDs may be very powerful these days. Look at the LED Beacons - those are single 40W LEDs, in such device you could fit tens or hundreds of 20-50W ones - it would be seen for miles, and could be actually blinding if looked at when on the deck (would probably need a power regulating circuit that would dim the lights after dark).
If there still would be a problem to pinpoint the location of the device on oil rig, it could also have a strobe, or the light itself could blink. As for power supply... that's no problem on the oil rig or a ship.
The presentation is very interesting and informative, I took liberty of providing it to pilots I know who fly to the rigs, and don't visit this forum. Although the main problem is of deterring "how fat, the 'fat egg' should be". Therefore an omni-directional system would give an definite answer to that - without guesing, see the green light = your on the glidepath.