Are butt joints okay in a raised cedar planter?

I’ve been building a few raised planters for my balcony (soil off the ground). I live in Canada (Zone 5B) and so we get a pretty wide ranging weather.

I’ve been following two general videos on YouTube when building my planter: [Video 1](https://m.youtube.com/watch?v=wtKYnta0MgM&pp=ygUacmFpc2VkIGdhcmRlbiBiZWRzIHBsYW50ZXI%3D) and [Video 2](https://m.youtube.com/watch?v=xuEusb_Ehks&pp=ygUhcmFpc2VkIGdhcmRlbiBiZWRzIHBsYW50ZXIgbW9kZXJu).

I’ve made the panels like suggested in Video 2, but I’m using 2x4 cedar for longevity and rip cut the 2x4s into 2x2s to use for putting the panels together.

My question is more about putting the panels together. All of these videos use butt joints for putting the panels together connecting them to leg. I’ve lurked around here for long enough to see people complain about wood expansion due to climate changes not being factored in. Do I need to worry about this when putting the panels together as everyone on YouTube seems to be doing? If not, why don’t we need to worry about cedar expansion with climate changes?