Novel models will probably need to have some custom layers, which are quite painful to write. The weights for the web version will probably be a low quality of what you achieve on a more powerful machine. And you don't need to provide the code for the training, nor the dataset used, so you will still have an edge over people copying you.
The main problem I have with tensorflow.js is that it's not production ready yet. It's probably 10 years ahead of it's time. Most people don't have recent GPU or recent video drivers. As it's doing some tricks with the GPU to have some acceleration, a fraction of your clients will encounter random bugs and crashes. I even got some bad review for causing reboots on Firefox :). For some people it will be so slow it will feel unresponsive, and others will find that it's unimpressive because you would have to use the minimal model. In a day and age where you need 99% satisfaction to exist, picking tensorflow.js is a mistake.
[1] chrome : https://chrome.google.com/webstore/detail/colorify/pipnfjhpb...
[2] firefox : https://addons.mozilla.org/en-US/firefox/addon/colorify/
[3] Wisteria : https://gistnoesis.github.io/