This depends a little bit on the level of bonus team you can field (which should be easy, given how many old and sometimes free units are bonus units for this event) and I'm not sure how interesting the math is, but here's my basic thoughts and assumptions:

• The 4 boxes of the box summon contain 39 sets of 10 50-nrg pots. This represents almost 68 days worth of NRG pots. Most people will have a bonus team that will only require a week or so to clear the boxes with naturally-generating NRG.
• After the boxes are cleared, the event summon still gives out the sets of 10 50-NRG potions at a rate of probably around 2.5-3% (I did 1000 event summons and got 27 of them, ymmv). Depending on your assumptions about where exactly that rate is and how often golden bombs happen, the break-even point is probably between 1500% and 2000% for your team bonus.

I get that we're all swimming in NRG pots anyways, so this probably doesn't matter to normal people, but if you're someone who likes optimizing ridiculous things like this, maybe you're like me and ramping up the rank farming with your extra NRG pots, this might be a weird opportunity to spend NRG to get even more NRG for later, and you also get low-tier ability awakening materials as a bonus.

Edit: After posting this, I realized that I think the 40-nrg version of the mission might be more efficient for farming than the 50-nrg mission, at least if finding companion units isn't a problem. The default amount of tickets per nrg is higher, and while golden bombs aren't quite as good when they show up, you can get golden bombs on two different rounds rather than just 1, which feels like it results in more frequent golden bombs, too.