Teachers can create subgroups and differentiate how the assessments are conducted and what each student gets assessed. Spelling City does a great job of that.
If the assessment is set at the students appropriate level then yes I think it could be considered inclusive. Is it not a teachers aim not just to find out what a student does not know thus be able to plan learning for ... but also to be able to recognise a student success and be able to commend and thus help build confidence and learning passion
I do like the idea of instant results and feedback and it makes a summative assessment, formative as the student knows what they need to improve and also what they're doing well and hopefully can prepare them better for their next assessment.
I do see your point about learners being more technology savvy these days, well teenagers especially and this could be a way to appeal to them. For adult learners though who haven't necessarily got to grips with technology to the same degree, I wonder if it would add another stress factor onto them as well as doing the assessment?
I do see technology increasing in education and can see the benefits, but was thinking on-line assessments might become more common place and was wanting to get people's views and experience about them.