I think, gifting bitcoins to your wife is not very good, unless your wife is a trader or interested in it. Since you said bitcoin is illegal, I'm not sure your wife would be interested in that, but if she likes it, then that's probably good enough.
It's just that, for the wedding day, it might be better if you sell some of the bitcoins you've invested in something that looks physical, or invest in real estate and give it to your wife. that way, your wife can show off something to her family that it is the result of your gift. well, i think it's more romantic. however, it all depends on you because she is your wife.