From my humble understanding, with LoRaWAN/TTN you're constrained to certain settings/channels/spreading factors/bandwidth etc. This is admittedly a good thing since all these settings are optimized, tested, and within the legal parameters in each region.
But you depend on someone else's gateway, or having to deploy and maintain one yourself. I saw one such commercial gateway once and all its hardware and it was not cheap at all, it has to be elevated to work well, has some serious antennas, not as simple thing as just whipping a Moteino with a RFM95 + monopole on your porch. I think these gateways also need to be able to run up to 8 channels in parallel. I am sure they can be made on your own.
Then there is the backend dependency of the network, which relies on the internet and their servers/cloud/whatnot to get your packet from a gateway to where it needs to go. LoRa is slower than FSK (bitrates) due to the way it chirps, so add to that the delays of relaying your packets through these networks, if that is relevant to your use case.
Up to you to decide if the benefits outweigh these limitations. If you're on your own, your code and hardware define your limits, no strings attached.