While the math might suggest the two are equivalent ratios of crank length to wheel diameter the riding experience is going to be greatly different.
I ran my 29 with a marathon supreme and that is a sweet quiet combination. You’ll be able to run higher psi for smooth rolling in the larger wheel with its larger diameter handling small road imperfections with less fuss.
The 24 will be more sensitive to bumps demanding more attention. Also less fly wheel effect to keep you rolling smoothly with less speed variations.
You should be able to average 8+'ish mph on the 29 with short cranks and skill : ) 100mm cranks are still pretty short and will take practice to get mounting consistent. Have fun!!!
I’ve recently been ramping up my road riding, I never did much before. On my 29er with 137mm cranks I’m averaging about 8 mph. I am by no means a fast spinner, but am working on it. I’ll be throwing on my 125s soon, I think I have an even shorter pair, but also have a fair amount of hills. I think a 9 or 10 mph average is doable with the setup you mention, but it will probably take some practice unless you are used to very short cranks.
the only time I would want a 24 for distance is if we were running racing standards. For 10k I would probably go 36 but 29 is a reasonable option as well. Plus the big wheel just feels great. Distance covered is a direct ratio of revs and wheelsize. Short cranks may make it easier to rev, but that is not a substitute for wheelsize in my opinion.
The only downside of the 29" would be its larger size, in terms of storage and handling. Definitely the better solution for your 10 km commute. Also, 8 mph (sorry we’re mixing miles and kilometers here) is on the low side. That would be a pretty comfortable cruising pace. If you want to get a workout, you’ll be going quite a bit faster on that.
Back in the day, I did a 9-mile unicycle race on a 24" wheel with the standard, 125mm cranks at an average 11 mph. On a 29" with 100s, that pace would be easy to maintain.