outside of japan, monacoin has limited potential. based exactly on what you said; its a meme coin for japanese culture. nem still has a much higher trading volume and is a better speculative investment. the price of monacoin just keeps tanking. not a lot of people understand that it wasn't nem's fault the exchange got hacked. the exchange had poor security practices. the price of monacoin just keeps tanking.
The network effect is key. If Mona becomes widely adopted in Japan, it will be used in other parts of the world too.
Today, NEM is down 7% in BTC terms while MONA only 2%...
These are completely different coins. NEM is a blockchain protocol like Ether while MONA is a classic crypto coin like Litecoin.
NEM market cap is 6.7 bln while MONA is 286 mln so I find it a better long term bet.