Yes the MR28 has no scanning radio, but the MR28 gets them 95% feature and API coverage for the best cost. Unless you very specifically need to test with those events I don't think it is worth it if your goal is to develop apps...you are better off using the sandbox for that last few %. Here is how other APs scale up to get that last 5% of features by list price (check with the retailer for actual):
MR28 - 95% compatibility with API endpoints and features, $500 list price
MR36 (gets you a scanning radio, no additional API coverage) $947 list price
MR36H (gets you access to port profiles (one or two additional API endpoints but more situational than other access points) $860 list price
CW9162 (gets you 6GHz capabilities, exposes some additional settings in RF profiles specific to 6GHz) $1595 list price