Personally, I think gachapon is a HUGE waste if NX Cash for a few reasons:
1) Using Gachapon Tickets is risky. You could get really bad items.
2) An average gachapon run gives you about 5mil per ticket at Zipangu: Mushroom Shrine.
3) Buying items out of the MTS and selling them for mesos probably can get you more mesos.
4) Takes a long time to sell off all those items and scrolls from gachapon.
5) Gachaboxes give much better items than gachapons.
6) Gachapons ussually give useless equips like level 30-50 items.
7) Just go get a NX look, no one wants to see you in a bathrobe.
If you have any other reasons why Gachapon is bad, leave a comment and I might add it to my list. If you disagree, you can also leave a comment with what you think.