I'm a teacher at a school with wealthy parents (£20k+ a year fees) Some do give extravagant presents but others more along the lines of yours OP. A token of appreciation is lovely.
I re-gift a lot (Gucci scarves, Chanel purses) but have kept every handmade card from a child I've ever been given. I've been given flights to a hotel in Spain owned by parents before, an iPad, a spa day (lunch, not included, cost me £35 
), a Go Pro and a hot air balloon flight.
Ironically, the expensive gifts tend to come from parents I see least of. The parents who do homework and read with their children, help with scenery and costumes and the Summer Fete etc are more likely to help their child make a card and some biscuits (or bag of chocolates) and they're the ones we love and know there's some thought behind them.
The best present I ever got was from all the parents and made with the class teddy which gets sent home and children write about.
The parents collaborated throughout the year and made a "What Zoe (the Zebra) Really Got Up To" book. Apparently she was in Stringfellows, met a punk band, fell asleep on a park bench; there were photos of her hungover, crying with running mascara holding a cigarette and empty champagne flute and having an affair on my classroom desk. One of my prized possessions simply because of the thought and time that went into it.
tl;dr - not naff. The idea is lovely. The poem could be naff if your daughter's copying something awful off the internet. A nicely written "Happy Christmas Mrs / Mr X" or "thanks for x, y, z" might be nicer.
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You're right that we're paid to do a job @SoulStew but that doesn't mean it isn't nice to show someone they're appreciated. I would never feel obliged to give a gift to anyone nor do I expect one but your attitude is quite recognisable as a 'type' of parent. I guess it's the same as a 'thank you'. Teachers don't need or expect them from children or parents but it's lovely to get one at the end of a long day or week.