It's definitely not mobile compatible yet. I think making it viewable on mobile devices soon is doable. Making them easily editable will be much harder / require a different interface.
I wouldn't worry about that just yet, even the Google spreadsheets dedicated app is a slow nightmare to use on the newest iOS and Android devices.
And to comment on the project, incredibly interesting. In my experience non-quantitative people (non STE-grads) tend not to be able to, at all, model decisions, decision trees and event trees as distributions or probabilities. This kind of decision analysis can be sold at very high margins, because it's value can be very high for the right audience. Intuitively, if you can form a solid business team and do enterprise/policy/strategy level sales, a company around this has a market (none of the established competing software pointed out by others is very cheap, and none of it is very modern, accessible or intuitive). Another option, more suitable for a freelancer mindset (and with a wider distribution of non-bust outcomes as well as arguably higher EV...), is starting and maintaining this as an OSS project, hopefully with a wide and growing contributor base; and establishing a career as a consultant in the modelling/predictions space with Guesstimate as your resume and business card. This of course depends as well on your personal interest - software developer vs. data scientist vs. fledgling capitalist.
And to comment on the project, incredibly interesting. In my experience non-quantitative people (non STE-grads) tend not to be able to, at all, model decisions, decision trees and event trees as distributions or probabilities. This kind of decision analysis can be sold at very high margins, because it's value can be very high for the right audience. Intuitively, if you can form a solid business team and do enterprise/policy/strategy level sales, a company around this has a market (none of the established competing software pointed out by others is very cheap, and none of it is very modern, accessible or intuitive). Another option, more suitable for a freelancer mindset (and with a wider distribution of non-bust outcomes as well as arguably higher EV...), is starting and maintaining this as an OSS project, hopefully with a wide and growing contributor base; and establishing a career as a consultant in the modelling/predictions space with Guesstimate as your resume and business card. This of course depends as well on your personal interest - software developer vs. data scientist vs. fledgling capitalist.