I don't think this is all that unusual in a church setting where the bride and groom (and/or their family) is very active in the church. They may not be close enough with the entire congregation to invite them to their reception, but many may want to attend the ceremony.

I do think the grocery thing is kind of tacky, but had it been worded differently, I don't think it would be all that unusual either. I would much rather give a gift that the bride & groom could use and if its groceries, then I am ok with that.