Can microwave with convection replace an actual oven?
You need to ask yourself what are you going to use more.

If you truly will never use the oven except for occasional baking, then go for the conventional/microwave combo, but if you are like me and use the microwave mostly as a tool to warm something or reheat something in quick order, then go for a proper oven instead, even if it's only a half size single rack oven.

I am not a big fan of microwaves. I use ours occasionally to soften butter or reheat left overs quickly and don't want to bother pulling out the skillet to do so, but those are both rather uncommon for me. I almost always heat up a skillet to reheat food under normal circumstances. I never actually cook in a microwave so take those as caveats to my answer.