Are there any disadvantages of building a receded base for a raised planter?

I've been going through a few ideas for the legs for my raised planters for my balcony, and I finally got a quote on 3x3 316 steel angle iron and it is way too expensive.

I came across this [Youtube video](https://youtu.be/aeyA10xIZ-g?feature=shared&t=1177) where she uses a receded base made out of cedar to use. I really like this design, but it is not commonly used and so I want to get feedback on whether this is a good or bad idea. There are two aspects I am wondering:

1. **Weight**. Will the cedar base be able to support the planter weight? As it ages, will it get crushed or cause the planter to get wonky? Will coating the cedar with something(?) make it last longer? Should I build the base with the 2x4s running with the 4" face outside or the 2" face outside? I feel like the 2" face outside will give better weight distribution. I am putting it in a balcony so it won't make contact with soil. 2. **Drainage**. I assumed since she is using these in a garden, drainage may not be a problem because it'll drain onto the ground below (although that cedar will still kind of stay soaked). Since I am using it in the balcony, I need to plan for drainage. I was thinking of using an "E" frame (think more like a serif E) with slots for me to put drainage trays underneath the planter and spacing out the bottom panels of the planter so that the water drains over the trays. Is there a chance this "E" design could cause any structural instabilities?